Q. Where can I find information on sales of books - statistics, numbers, etc.?

The Nielsen BookScan data is the primary source for book sales figures, however UVA doesn't have access to this resource.   Publishers Weekly and Factiva include articles on sales of books. 

Additional sources include:

• Market Share Reporter   in print at Darden (and available to the Law School online in Lexis Nexis) has some information on market share for books and publishers.
• The Library and Book Trade Almanac  in print Reference - Z731 .B6 - also has information on sales numbers.
• AAP collects statistics and will sell them - https://publishers.org/who-we-are/

For older books, it can be worthwhile to contact publishers, or consult their archives; SHARP maintains some links to publishers' archives here: https://www.sharpweb.org/main/archives/