E-books are electronic versions of books that can be read on a computer or other electronic device. Unlike ink and paper, there is no standard format. Adobe, Microsoft, and others use their own formats and Amazon, Sony, and others have issued portable readers for e-books with proprietary formats. In addition, digital rights management may not allow works to be shared with others who have the same device.
The advantages of e-books include bookmarking, annotation by the reader, full text searching, and adjustable type size. Portable devices allow the user to carry and access numerous books in a minimal amount of space compared to the size and weight of paper books. Users also can obtain their reading material, some for free, by downloading rather than going to a brick-and-mortar store or having it shipped to them.
Criticisms of e-books include readability issues, battery life, and the inability for some graphics or other content to be reproduced. In addition, while the cost of e-books is generally less than the physical copy, there are complaints of price given the comparative cost of production and distribution. One of the biggest criticisms though, is that it's hard to curl up with an e-book.