I am choosing fonts for book design and want to know what font the average book uses? Is it possible to use calligraphy as a font in a book?
Choosing a font is a strictly stylistic choice where the font should match your subject and your way of writing. For example, using a silly font like jokerwood for a serious nonfiction piece could be considered an incorrect utilization of font. Here is a link with the top 10 most widely used fonts used by book design winners: http://fontfeed.com/archives/top-ten-typefaces-used-by-book-design-winners/
Common typefaces include Minion, Adobe Garamond, Caslon, and Palatino.
The typeface can depend on what type of book (fiction? nonfiction? kids' picture book?), and what type of text (body, chapter title, title, subhead, etc. etc.). A calligraphy-style typeface might be acceptable for a title or heading, but it'd most likely be hard to read with body text. I'd probably advise against it.
Choosing a font is a stylistic choice, but keep in mind that the font and design of your book have to contribute to a comfortable reading experience.