It’s a portable screen about five to seven inches in size that displays pages from books, periodicals and documents and uses a rechargeable battery. Such devices are optimized to let you download content from online libraries. Although most eBook
readers are preloaded with sample selections, you update content in your reader as desired. Because bits are weightless, carting an entire stack is no more difficult than carrying one novel; and the entire eBook reader takes up less space than one hardcover.
Decide whether you want a dedicated eBook reader or a multi-function tablet. The former will be smaller and lighter; the latter larger and brighter. With a tablet the time between battery charges is measured in hours; an eBook reader's charge can last for weeks. A tablet is a computer that easily diverts you from reading since it also plays video and lets you access the full scope of the Internet.
An eBook reader will always come with a cable that plugs into the USB port of your computer so you can download new content even as the cable charges the eBook’s internal battery. You use your computer to first download books from the Internet—typically from the online store run by the eBook’s manufacturer. (There are usually alternative sources, especially if the eBook reader recognizes a variety of formats—more about formats later.) If it’s important to be able to load new content when you’re away from your computer―say, while you’re waiting to board a plane―you may want an eBook reader with built-in cellular network data reception. You’ll be able to access the eBook maker’s store, buy digital books or newspapers and download them directly into the device. There’s no fee for air time, so you could just browse the store, but you can’t connect to other sites or call someone.
Like portable media players, iconic controls that appear on the touch screens of eBook readers are eclipsing hard buttons. The advantage of touch-screen devices is that the display can extend to the bezel, which means the eBook can be made smaller and lighter than one with a full set of hard controls. Still, some people prefer dedicated buttons apart from the screen.

Since physical books contain mostly text, an electronic device that displays high-contrast black letters on a near-white background should be all you need. Color adds little to the experience of reading most books. Since all eBook readers also let you view images, you should still be able to view a book’s diagrams, line drawings and photos on the monochrome screen. However, as magazines migrate to e-readers, color will play a more important role.
That means, of course, that the device can play audio. Reading purists may argue that such a feature is irrelevant. Yet, there are practical reasons to choose a reader that plays music. Suppose you want to block out someone's phone conversation during your commute so you can concentrate on your reading. Why juggle a second device when you can load your music on your reader and have it drown out irritating banter? Also, some readers are compatible with audio book formats such as those from Audible (a company that pays actors or the author to make a studio recording). Still others can convert text in the eBook on the fly using a synthesized voice. If the eBook reader contains an earphone jack or speaker, you can bet that the player will be compatible with MP3 files. It may also play WMA, AAC or WAV files.

A typical eBook reader will recognize both protected books you buy or borrow online and unprotected documents that can be readily copied from your computer. Depending on the eBook reader manufacturer, proprietary formats include ePUB and BBeB; open formats include PDF, TXT, RTF, HTML and Word documents.
What about image formats?
Most eBook readers can display JPEG, BMP, GIF and PNG files, albeit in black and white. A handful can also show TIFFs. For graphics, the more shades of gray, the better. Hence, an eBook capable of 16 levels will reveal more subtleties than one capable of eight.
How adjustable should the text be?
No matter the book, you should be able to incrementally set the font size from small to large, so you can find the best personal balance between readable text and fitting as many words on the screen as possible.
Also, if you turn the screen 90 degrees the text should reorient from portrait to landscape mode and vice versa, automatically or by you pressing a button.
Absolutely. Nothing is more convenient than being able to pull up a definition at the point of need. Some readers even contain translation dictionaries to other languages.
You can typically jump from one book to another, and the e-reader reloads the screen at the point where you left off. This passive bookmarking is referred to as auto bookmarking. But some e-readers let you actively insert multiple bookmarks. And some enable you to highlight text and write linked notes using an included stylus on a touch screen’s sketchpad window or via an onscreen keyboard. Some non-touch screen models contain a mini keyboard below the screen. If you’re a student, multiple bookmarks, highlighted text and annotations are
must-have features. If you’re a leisure reader, such features are less compelling.
Compared to videos or high-res photos, text doesn’t need lots of storage space. Hundreds of books can be loaded into a gigabyte or less. EBook storage comes in the form of models with internal flash memory or a memory card or both. A reader with internal memory usually contains 1 to 2GB. A model with a card slot will typically accept an SD/SDHC or microSD card. The advantage of a card slot is that the eBook reader’s memory is expandable and libraries are manually swappable. When a model‘s storage is confined to internal memory, new content can only be loaded via the included USB cable (or wireless connection), and if there’s insufficient capacity left over for new content, you must delete a currently-loaded book to accommodate something new.
The Takeaway