In May, a well known book-seller made headlines when it reported that it had sold more electronic (or "e") books than it had the dead-tree variety. With libraries loaning out e-books, college textbooks slowly making the transition and a growing catalog of titles to choose from, it's clear that e-books are winning over converts by the thousands.

It's also clear why e-book readers are succeeding. E-book readers are light. Amazon's Kindle weighs just 8.5 ounces, lighter than most paperbacks and certainly most hard bound books. They also store thousands of books on their internal memory. You can never run out of things to read (making you the modern-day equivalent of Henry Bemis, without the unhappy ending). It takes minutes (or less) to get a new book delivered right to your lap, without a drive to the bookstore (or library) or waiting patiently for a book to arrive via the U.S. postal service.
Before you dive into this digitized world, there are a few things you should keep in mind before you make your e-reader purchase.
Display: E-book reader displays usually range in size from 6 inches (think about the size of paperback book page) to about 10-inches.While the majority are black-and-white displays, there are a growing number of color e-book screens coming on to the market (much better for illustrations and photographs).
A dedicated e-book reader usually uses a form of "e-ink" for its display. Unlike an LCD display found on tablets, e-ink screens are not backlit so text is much easier to read in bright light conditions. It looks much closer to a printed page than a laptop screen. The downside: The lack of backlighting can make e-books harder to read in lower light than a backlit screen.
Touch-screen displays are also available on several e-readers. Using a touch screen you can simulate page turning with the swipe of your finger. Other readers have small buttons for flipping pages, which minimizes smudges on the screen. Readers with touch screens will provide "virtual" keyboards for you to use when searching for the latest bestsellers.
Connectivity or How You Get New Books: Many e-book readers are increasingly bundling wireless connectivity options for downloading new books. This way you don't have to connect your e-book reader to a computer (of course, you'll need a wireless network to take advantage of this function). Wi-fi is a popular option although you can also find e-book readers that support 3G cellular wireless connectivity as well for a truly mobile experience. But while you'll find Internet connectivity, most dedicated e-readers don't really give you a full web browsing experience. You'll connect to e-book stores but you can't go surfing the wide world of the web (this is slowly changing, though).
Which books are available?
As far as your options in e-books themselves, they're expanding. Rapidly. First, you can tap into a growing library of free publications from Google Books (these are public domain titles, including many of the classics which you know you need to read but probably haven't yet). Depending on the e-book reader you own, you can also download free e-books from your local library. Sony's Reader, for instance, supports this useful function, and Amazon announced in April that it would team with over 11,000 libraries in the U.S. for Kindle e-book lending. All you need is a library card from that particular library and an account with Adobe.
Not every library in the country is offering e-books for download, but many are, and like a regular library book, the e-book is free to borrow for a time-limited basis. If library rentals are important to you, check with your local library to ensure they support a particular e-book reader you're considering.
As far as e-books to purchase, buying an e-reader usually the determines the e-book store you will access. Purchase a Kindle, you'll be using the Kindle store (aka Amazon). Purchase a Nook, you'll be buying your e-books through Barnes & Noble. Purchase a Sony e-reader and you'll be buying from the Reader store. And so on.
E-Book Reader or a Tablet?
You may be asking yourself which device is right for you since both can tackle e-books. The answer depends on what you want to do. If you're looking at a tablet, like an iPad or a Motorola Xoom (shown below), simply because you want an e-reader, it's probably not worth it. E-book readers will be lighter, less expensive and the e-ink displays provide more of a "print page" feel. Most of the hard-core book lovers I know prefer to read books on an e-book reader (even if they own a tablet).

On the other hand, if you want a more multifunctional device that surfs the web, plays music and videos and, oh yeah, can display e-books, then a tablet is probably the way to go. Some e-reader makers have apps that you can load onto your tablet so you can access their e-book stores and download books - no matter which brand of tablet you own.
You'll pay more - an iPad retails for $499 and up while Sony's Reader goes for $230 - but you'll also get more functionality from a tablet.
An Open Book: Here's a look at some hot-selling e-book readers

The 70c from Archos ($119) sports a 7-inch touch screen display with a resolution of 800 x 480. It offers built-in Wi-Fi and in addition to e-books, can display photos, videos and play back digital music. It offers 4GB of built-in storage with a slot for SDHC cards (up to 32GB in capacity). It weights 13 ounces.

Aluratek's Libre is a bit smaller at 5 inches but comes bundled with both a 2GB SD card and 100 pre-loaded e-books. There's no internal memory, but the SD slot on the Libre supports cards up to 32GB in size. It has an "e-paper" display for simulating the look of real book pages and a sports a battery capable of 24 hours of continuous use with an auto-shutoff to prevent battery drain when the device is not in use. In standby mode, the battery on the Libre lasts for two weeks.

A good straight-ahead e-reader is the Ematic eGlide 7-inch Color Touchscreen Internet Tablet ($139.99), capable of displaying and storing more than just e-books. It features a 7-inch TFT touch screen with 800 x 480 resolution with 160k colors. It ships with 4GB of storage that can be expanded to 20GBs and so it's a good platform for storing e-books, music and video. Additionally it has built-in Wi-Fi to ease downloading new e-books and has the ability to connect to a TV or computer to stream videos and has the ability to transfer books and music back and forth between with a computer. Also available in Pink.
So, what about the biggest selling tablet of them all? Read Greg Scoblete's full review of the Apple iPad 2!