eBooks in one format or another have been around for a long time, but are really starting to catch on with the birth of so much new technology to support them. As with all new technology, though, there is a plethora of providers, each offering products they hope will eventually dominate the market. For those of you just looking to buy and read a digital book, this conglomeration of formats and devices can be overwhelming. Let's break down the existing options, so you can better understand them.

Definitions

An ebook is any work of fiction or non-fiction that can be downloaded or delivered to you in a permanent digital format. You should be able to save it somewhere and read it any time without having to re-connect to the internet. If the information is only available on a web page to read when you're online, then it's not an ebook; it's web content.

An ebook reader or ereader is a physical device whose primary purpose is reading ebooks. Examples include Amazon's Kindle and Barnes & Noble's Nook, but there are many others. Understand, though, that you don't need a dedicated ereader to read an ebook. You can read ebooks on a desktop or laptop PC, a phone, a tablet PC, and probably some devices I've never heard of.

There are dozens of ebook file formats on the market right now, though three formats prevail—PDF, EPUB, and MOBI—making up almost three-quarters of all ebooks, according to a 2010 survey by Smashwords.com. The file formats are simply different schemes for storing a book's contents in digital form, just as JPG, GIF, and TIFF are different ways of storing a digital image.

eBook software is the program that tells your device how to display that digital file so you can read it. Each of these programs will have a unique set of features, like the ability to adjust font sizes or styles, flow the text, bookmark locations, or highlight passages. This is analogous to image-manipulation software such as Adobe Photoshop or Corel Paint Shop Pro, which each have their own features for editing images. The most common ebook reading software is Adobe Reader, which displays PDF files, but only PDF files. The software on the PocketBook Reader, on the other hand, can display a dozen different ebook formats.

The Software-Device Connection

While dedicated ereading devices come with their own proprietary software, it is important to realize that most ebooks can be displayed on multiple devices, if you get the right software. For example, many people think that books found in Amazon's Kindle store can only be read on a Kindle device. Not true. Amazon's Kindle software is available free for the PC, iPhone, iPod Touch, BlackBerry, iPad, and Android devices. And if you don't have one of those, you still may be able to read the book on whatever device you do have, if you convert the file with a free ebook file conversion program such as Calibre. The same is true for other ebook readers.

In fact, the only books you cannot easily port over to other software or devices are those that have been created with DRM—digital rights management. DRM is copy protection for ebooks, and many of the big-name publishers refuse to produce ebooks without it. The (enormous) downside to DRM, of course, is what I just mentioned. If you have a legally purchased DRM-protected ebook, you cannot use the file in another format or on another type of device. That means if you buy several DRM'd ebooks for your Kindle or Nook, but later decide to switch to a Kobo Reader, you are out of luck. You cannot read those books on your new device without breaking the copy protection. I'll leave the ethics and business practicality of DRM as a subject for another day.

So remember, ebook file formats are just different ways of storing the digital content of a book, and ebook software is used to decode that content so it can be displayed according to your preferences on a reader. Digital rights management aside, with the help of a conversion program, you can read just about any ebook on just about any device. If you're ready to try an ebook reader, check out the Amazon Kindle or Barnes & Noble's Nook.