Q: How can i delete a book from my purchased book's list

Hi Parsa2014,

Thanks for the question. The following resource outlines how to delete various types of content from an iOS device:

How to delete content you've downloaded from the iTunes Store, App Store, iBooks Store, or Mac App Store - Apple Support

http://support.apple.com/en-us/HT5772

If the content is not downloaded to your device, and you would instead like to remove the book from your purchase history, you can accomplish this by hiding the purchase:

iTunes Store: Hiding and unhiding purchases - Apple Support

http://support.apple.com/en-us/HT201322

- Matt M.