The word "ebook" stands for "electronic book." And it is just that: an electronic version of a printed book that can be read on a computer or digital reading device.
Ebooks come in a variety digital formats. The most popular is the PDF; others include Microsoft Reader, Microsoft Word and MobiPocket.
Ebooks can be read on computers, but the ebook reader is the most popular device used to read ebooks. The most popular readers are currently the Amazon Kindle and Sony's eReader. Prices range from $199 to more than $400.
Ebooks are available at most online bookstores, as well as popular etailers and music-sharing sites. Ebook prices vary widely, from free to the same cost as a new hardcover.
Ebook sales grew 150 percent in 2009. Similar growth in ebook sales is expected, indicating that the once "novel" ebook is here to stay.