How do you cite a book that is completely online?
Thank you for your question. I assume that you are using MLA citation. If so, it follows the same format as for a print book, but instead of "Print", "E-book" is listed as the medium. Here is an example from A Pocket Style Manual ("Hacker Manual"), MLA 33b, p. 146:
Tolstoy, Leo. War and Peace. New York: Knopf, 2007. E-book.
If using another style the Hacker Manual also has directions for APA (p. 188) and Chicago styles (p. 200). Please let us know if you have any additional questions.