The category is reserved for Book (really eBook) reviews. If you want reviews on eBook Readers see: Hardware Reviews. See eBook blogs for web sites that have eBook reviews. See also the MR Book Club Selections with forum discussion.
 Writing eBook Reviews
The person doing the review should be mentioned on the top line after a repeat of the author and title with whatever explanation and expansion is deemed appropriate. If the user is logged into the wiki then their name and date can be easily entered by using 4 ~ in a row ~~~~. For example when I do this I get: DaleDe 13:15, 6 March 2008 (EST). You can also tap on the signature icon above the edit window to get this.
The convention for a book review page will be to start with the last name of the author then a comma and then first name. A colon separates this data from the Title. If you type this in the search box you will get an opportunity to create this page. Alternately you can tap the discussion tab above this page and edit the entry to make the new page. After you save the edit you tap the entry on the discussion page to create the new page for your review. (This may be easier to see what you are typing for long titles.)
The page should typically have a top line as mentioned above and then two sections named ==Review== and ==For more information==, the latter used for links. It is a good idea to link back to a forum thread if the review is also posted there. This way comments will readily reached. You could also just start a thread and point to the wiki review.
At the bottom of the review the words [[Category:Book reviews]] should be entered as shown with the brackets. This will cause the review to appear in this category listing.