iPhone/iPad e-book app review: iSilo

isilohelp If you’re wondering whether the iSilo reader (v5.17) for the iPhone and iPad is worth the hefty $9.99 cost, the answer depends on whether you’re within its target audience. If you need to mirror web documents or sites on the iPhone with an absolute minimum of time and effort, particularly those heavy on tables, iSilo is definitely for you. The availability of iSilo reader apps for a fairly large number of other devices and platforms is another plus.

Likewise, if you are a member of the medical or legal professions, you will find a considerable amount of useful pre-made iSilo content available to you. However, if neither of these conditions applies, you can probably give iSilo a miss.

iSilo and its free document converter iSiloX make up an extremely powerful tool for taking web content with you wherever you go. The downside is that, as with many powerful tools, its user interface can be a trifle arcane and hard-to-understand, especially for new users.

Parts of this review are taken from my review of iSilo v1.31 for the iPhone, updated to reflect changes.


Back in the ‘90s, when Peanut Press and MobiPocket and others were concentrating on making print books readable on PDAs, iSilo was coming at things from a different direction. Whereas the other formats were trying to replicate the printed-book experience on the small screen, iSilo was most concerned with replicating webpages on the small screen.

Over ten years later, iSilo is perhaps the only original e-book format company left that is both still active and under its own ownership. It has accomplished this largely by “staying beneath the radar”—unlike MobiPocket or eReader, iSilo never tried to become a widely-adopted mass market e-book format. Instead, it took laser aim at a very narrow market segment and concentrated on meeting that segment’s every need. iSilo is the professional’s e-book format.

Doctors and lawyers have one significant thing in common, besides being highly-paid professionals. They both need ready access to vast amounts of information. There is much more knowledge about the human body and about the law than any one person can remember, so part of a doctor’s or lawyer’s repertoire is the ability to know how to look things up.

If you thought that college students have it bad today with heavy textbooks to tote around, doctors and lawyers often need entire libraries’ worth of books. Even if they mostly use only a few of those, they can’t exactly have even those few with them wherever they go. Or at least, they couldn’t before the PDA came along.

But the downside of most e-book formats then, as now, is that they tend to focus on the subset of HTML most suited to making prose look pretty. Not a lot of thought is given to the sort of reference tables that make up a lot of medical or legal texts. But that’s where iSilo comes in.

iSilo is designed to duplicate websites, including tables and links, as closely as possible on the iPhone to how they are on the web. Its complicated conversion app, iSiloX, is part formatter and part site-scooper. Thus, those with medical or legal texts to format were able to convert them readily into iSilo—if they could make the necessary table in a webpage, they could make it in an iSilo book. Thus, medical and legal professionals were suddenly blessed with the ability to carry sizable tomes around, digitally, in their pockets.

And once all those tomes had been converted to use this perfectly-suited digital format, what need did those professionals have to change it? This inertia, combined with a lack of attention on the part of most other e-book formats to properly rendering tables, has lent iSilo a considerable amount of staying power over the years.

Consequently, iSilo is used by packagers of documents for the legal and medical professions to this very day; you can still find a number of sites offering iSilo books both free and for sale on iSilo’s links page. Apart from use on a number of public-domain sites such as Munsey’s (nee BlackMask.com) or Memoware.com, iSilo never saw much use for general e-books (though I personally used it to convert the Baen Webscription titles I bought way back then, because I didn’t like the Palm MobiPocket reader’s wide margins).

So, if you do buy the iSilo reader, you should probably expect to use it mostly for e-books you make yourself—though, as I will cover later, doing so really isn’t all that hard.

iSilo’s long life means that there are versions for a remarkable number of platforms, including the original Palm OS, various flavors of mobile Windows, Symbian, S60, Blackberry, iPhone OS, Android, Mac OS X, and Windows desktop. All these platforms are kept current with the very latest version of the iSilo reader.

And given that iSilo has not yet been bought up by a competitor, it was able to bring out the iPad version very shortly after the iPad’s launch—and is perfectly free to develop a reader app for any new platform that should come along.

Of course, iSilo does charge for these apps, and always has—and except for the $9.99 iPhone version, they cost $19.99 each for full functionality. The “free” versions of iSilo disable a number of the app’s most desirable features including links, images, color, and tables.

$20 may be considerably more than such an app would be worth to you, but again, iSilo’s niche audience is made up of highly-paid doctors and lawyers to whom $20 for an app would most likely be a pittance.


On the iPhone and iPad, iSilo books are displayed by default in a Verdana sans serif font. They can be viewed in either portrait or landscape; iSilo has a very smooth accelerometer screen-flip function. The documents look very much as they did in their original HTML format (making allowances for screen size in the iPhone version), including italics, bold, links, and even tables.

Unlike a number of other e-book apps, iSilo does not seem to have any easy way to hide the upper and lower toolbars—it requires going all the way to the bottom of the Options menu and choosing “Full Screen”. This is not so bad on the iPad, but definitely noticeable in lost real-estate on the iPhone.

The font is reminiscent of the fonts available on the old PalmOS devices where iSilo was born. Someone used to reading on those devices might see very little difference in how the document is displayed.

However, these days I tend to prefer reading in a serif font, such as Georgia, for the way it guides the eyes along. iSilo does have a font-setting dialogue under its Options menu, where the font can be changed to any that is available on the iPhone—but the font change dialogue was confusing and did not seem to work when I originally tried to change the font.

I was then informed that this has to do with the way that iSilo documents have a specific font family (serif or sans serif) set, and you must choose which font is displayed for each family, then choose which font family to view the document in. You can choose to set a serif font to be displayed for sans serif families, by turning “Set Defaults” on, changing “Family” to “Sans Serif,” and then choosing the serif font, such as “Georgia”. I tried this, and it worked. Still, it only serves as more evidence of the overall clunkiness of the application and its configuration options.

Another missing feature that would be nice to have would be a way to zoom in or out, using the standard pinching and widening models. iSilo doesn’t have that, and it’s not terribly easy to change font size using the menus.

isilo-table iSiloiPad 002Clunkiness aside, one place iSilo really shines is its ability to display tables. For a test, I pointed iSiloX at the famous MobileRead Wiki E-book Reader Matrix, a very extensive set of tables table listing the relative abilities and specs of dozens of dedicated e-reader devices, then examined the resulting file on both my iPod Touch and my iPad.

In both cases, it reproduced the tables faithfully (though my slower iPod Touch did show the table unformatted for several seconds while it churned away to render it)—I had to scroll both horizontally and vertically to see the entire thing, but the table is so large that scrolling is necessary on full-sized monitors too. I now plan to keep the table on my device for showing other people who have questions about e-books, given how convenient it is to have that information close to hand.

And it was easy to set up, too. I just entered the URL in iSiloX and that was that. The entire process only took about a minute or so. (More on that process below.) By contrast, the only way to scoop a site for use with Calibre is using a confusing command-line-only Python app bundled with it, which I tried a couple of times and then gave up on. I still don’t know how EPUB reproduces tables, but am having a hard time believing it could work this well or easily.

Unlike other iSilo clients, the iPhone/iPad version of iSilo has been blessed with the ability to display several document formats in addition to iSilo—most notably PDF, Word, RTF, unaltered HTML, as well as JPEG and other image formats. No conversion is necessary to load these documents into iSilo. Perhaps the iSilo people figured that these document viewing abilities might make the iPhone version of iSilo more attractive to people who had never used it before.

Most of the PDFs I loaded as a test in my review of the earlier version of iSilo displayed adequately—at least as well as they would appear in Air Sharing’s viewer. The only failures were a Wowio PDF (which only displayed the first couple of pages and everything else was blank—perhaps this was due to whatever copy protection method Wowio uses) and my 153-megabyte Spycraft 2.0 PDF (iSilo churned gamely away for a couple of minutes trying to load it, then the iPod crashed to the silver-apple screen—but then, I didn’t really expect it to work).

To note, I did not deem it necessary to re-try PDFs extensively while reviewing this version of iSilo to see if anything had changed, since there are much better, cheaper ways of viewing PDFs on the iPhone and iPad now.

Ease of Use

Both having names that start with a lower-case “i,” it would seem that iSilo and the iPhone or iPad were made for each other. At $9.99 on the App Store, it is half the price of the iSilo client for other platforms (though this price may be raised at any time).

Like other platforms’ iSilo clients, the iPhone version is capable of reading iSilo-format documents. However, unlike the other versions, the lack of hardware buttons on the iPhone leads to some hard choices in the user interface.

Scrolling up and down can be done by dragging and “flicking” just as with other iPhone apps. But there are other functions that can be performed by single, double, or triple-tapping the screen at various points. (They can be edited from within the Options menus.)

Tapping in the very middle of the screen brings up a display of the single-tap commands, then tapping again in the same place switches to the display of double-tap commands (as seen at left), then triple-tap.

Thus, tapping twice in the lower left corner of the screen would move to the previous page in the document, or tapping twice in the middle top would page up. The interface is a bit clunky, with so many different locations and taps to remember—and if you are in the habit from using other applications of just tapping anywhere in the lower part of the screen, iSilo could be a little hard to get used to.

One thing I have found while reading documents in iSilo is that sometimes the scrolling can be decidedly sluggish. Sometimes it will not even scroll at all, no matter how much I flick it—and then it comes unstuck and immediately jumps several pages down.

Another mild annoyance has to do with the “soft” scrolling selection from iSiloX—a format conversion option which is supposed to allow scrolling across boundaries between different webpages in the same iSilo file.

I used soft scrolling with Baen Webscription books (which are set up in a one-webpage-per-chapter format) when I was using iSilo on my PalmOS machines so I would not have to click a link to jump to the next chapter, just hit the down button again to scroll across the boundary. However, the iPhone iSilo client does not seem to recognize soft scrolling. (I wonder if it is because of the same API issue that makes BookShelf have to load books in 35K chunks?)

Another place where the interface is a little clunky is in the configuration menu (accessed by tapping the “More” icon at the lower right corner of the screen). This will bring up a list of all possible functions—File, Edit, Find, Mark, Go To, and Tools—in one single panel. It should be noted that iSilo is one of the most configurable e-reader clients I’ve ever used—but there are so many choices that they can end up being rather confusing.

For instance, if you want to change the font, you need to go to the “Edit” section and choose “Options”. The options for autoscroll, rotation lock (to prevent the screen from changing orientation if you flip the device on its side), and full screen display are under “Tools,” at the very bottom.

Thus, to engage full-screen mode (getting rid of the title bar at the top and the menu bar at the bottom), you must go into the configuration menu and scroll to the very bottom. (Also, if you attempt to page down with a tap, you will come right back out of it again, since it is turned off by tapping at the bottom of the screen where the menu bar would be.)

However, I have been informed that these functions can be mapped to single, double, or triple tapping particular areas on the screen, so a user who used these functions often might map them to be called up easily.

Adding Content

isilox In order to convert documents from HTML into iSilo format, you will need to download  the free iSiloX converter program. This program will allow you to convert any single page or collection of linked pages into an iSilo-compatible e-book.

As shown at right, iSiloX offers an incredible variety of formatting options that can be set for the documents it converts. I don’t even understand what half of them do, but can manage to get decent results just twiddling with the ones I do understand.

Once a conversion scheme for a site is defined, it can be saved into an .ixl configuration file and reloaded in the future, just in case the content of the converted site should be updated.

Some websites, such as Munsey’s, also offer preconverted iSilo-format books for download. (It should be noted, however, that Munseys uses an older version of the iSilo format, which shows up double-spaced on newer iSilo apps, so you will get better results if you download or copy the link to the HTML version and convert it yourself.)

iSilo is a format that has been evolving since shortly after the introduction of the original Palm Pilots. At its root, it is intended as a way to take text formatted in HTML and translate it to a form that can be read on a PDA, with as little human intervention as possible along the way.

In this respect, it has a couple of notable advantages over another HTML conversion document format, MobiPocket. With iSilo, if you have a table of contents for a book in HTML format with links to all the chapters, all you need to do is point iSiloX at the table of contents and tell it to fetch that to a link-depth of 1. It creates the book for you, with the table of contents at the beginning—and links from the table of contents to other parts of the book work just as they would if you were viewing through a web browser.

On the other hand, I have never yet been able to make a MobiPocket-converted file with a built-in table of contents, even when I had that same table of contents HTML file.

This also makes iSilo a natural for mirroring websites. Just feed iSiloX the URL and link depth, and it will produce an archive file that can be browsed just as if it was the actual website. Of course, this was most useful back in the PalmOS days when the presentation of the web on a portable device was much more limited—but even now, with all the iPod Touches and wifi-only iPads in circulation, there’s no guarantee of being able to access the web at any given time.

iSiloiPad 003Paradise by iSilo light For example, I fed iSiloX the URL of the main table of contents page for the Paradise setting on Shifti, with a link depth of 1 and no off-site links allowed. One quick load into iSilo later, I had the whole thing on my iPad, and clicking on any given story would take me there.

I also use iSilo to keep a copy of the EarthDawn 1st Edition RPG, which was released in HTML on CDROM years ago, close to hand. I have never had the chance to play it, but I find it neat to have it available.

Once you have files in a format iSilo can read, it is necessary to load them. As with eReader, iSilo can pull down compatible files from any web server, including one on your own desktop computer, using an internal browser window. But unlike eReader, iSilo also offers the ability to load files into its memory without needing a webserver or any specialized PC-side conduit at all.

Like GoodReader, iSilo has its own WebDAV server built in. This means that you can tell iSilo to set itself up as a file server—a virtual hard drive on your wireless network which you can access with a URL. You can then add it to “My Network Places” on your Windows computer, explore to it, and move files into and out of it just as you would any network drive. In short, the app itself is also its own conduit.

This also means that you can use iSilo just as you would Air Sharing or GoodReader—as a network hard drive utility to transfer files from one computer to another without ever wanting or needing to view them on the iPhone.

Loading files in this way is easy and fast, at least for me. It means no having to mess around with a conduit app that may not actually work properly. In my original review, I said that I wished other e-reading apps would offer this function—but now it seems that many of them actually are.

In addition, iSilo for the iPad can be loaded using the “File Sharing” section of the Apps sync tab.


$9.99 may be a bit much to pay for an e-reader app these days. Even BookShelf, which started out that high, came down to $4.99. On the other hand, iSilo does offer near-effortless site mirroring and excellent presentation of HTML tables, something that no other iPhone or iPad e-reader I have seen can manage.

Aside from legal and medical professionals, anyone who has to refer to a lot of HTML files or websites involving tables could certainly make use of iSilo—role-playing gamers, for instance (if they have games rendered in HTML, which is admittedly pretty much a rarity).

The flip side of the coin is that the app and its converter are so complex that beginning users might have a hard time making sense of all the options available to them, and the user interface is still a little clunky.

In the end, iSilo is a reasonably well-made app for a format that has been undergoing continuous improvement for over ten years and shows none of the signs of abandonment seen in readers that have been bought out by other companies. It might not be best suited to general-purpose reading, but is unparalleled within its niche.

4 Comments on iPhone/iPad e-book app review: iSilo

  1. Mr. Natural // May 20, 2010 at 8:40 am //

    iSilo’s perennial problem is that the converter is free while the reader application costs money. This bass-ackwards business model has long kept iSilo an undesirable platform for E-publishers.

  2. Sorry to hear that the developer still hasn’t fixed the scrolling problem! It’s a nuisance, sometimes herky-jerky on the other i-devices, too.

    You are also right about the convoluted interface and command structure–and this is coming from someone who has used iSilo for years. It uses a confusing, parallel folder, category, & device structure which is beyond most casual users.

    What it really needs is an ability to automatically fetch the web pages that one sets up for it… the current two-step process of having to use the laptop or desktop computer to fetch the content and then set up and run a wireless sync is now arcane. I used to use iSilo for newspaper and newsgroup reading, but it’s now easier to use such apps as the New York Times or Huffington Post, or an i-device’s browser to read web pages.

    iSilo served a real purpose in the old Palm days when wireless browsing was either non-existent or impossibly slow.

    But today? With such products as Instapaper and ReadItNow, which are cheaper, and permit saving of any web page you browse to, iSilo’s raison d’être seems undermined, sad to say.

    Still, the developer could rescue the app by a modern overhaul. Hope it happens!

  3. I am in a comunity of Christians world-wide of maybe a couple million who extensivly reference a study bible and a body of literature by Watchman Nee and Witness Lee. Isilo is very standard for us. A few people have done book conversions and everyone shares. The hymnal and various songbooks are also used on isilo. Living Stream Ministry, the publisher, even sells the bible and many books in the iSilo format with password protection. In my opinion iSilo’s biggest lack is an integrated book store.

  4. At this time it seems like BlogEngine is the top blogging platform available right now.
    (from what I’ve read) Is that what you’re using on your blog?

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