Responses are starting to come in at the thread I created some weeks ago to prepare for this thread.
Please use this thread, from now on, to report your numbers if you are so inclined. I reported 4,086 volumes as of May 25. However, I'd forgotten my own principle #4 below, which will add about 100 volumes to the total.
Here were the criteria that I proposed to follow for what counts as a book. No one is obliged to follow them.
1.Electronic books don't count.
2.Telephone books don't count. (See also #7 below.)
3.Books that are yours only for use during your time on a job don't count.
4.Bound volumes of magazines do count, but loose magazines don't count.
5.Items that one has bound with staples don't count as books. (I have a number of novels that I downloaded from Project Gutenberg, printed, and bound with large staples. I'm not going to count these as books.) However, something like a fan-published book that is bound with staples will count. I have Harry Warner's fan history A Wealth of Fable in the form of three mimeographed and stapled "volumes." It will count as one book. (But see #8 below.)
6.Diaries, personal journals, scrapbooks, and photo albums don't count as books.
7.Ephemera such as Penney's or Monkey Ward's catalogs, paperback almanacs, college catalogs, and bookseller catalogs don't count, but school and college yearbooks do count as books. I own four city directories. They will add four books to my count.
8.Each volume of a multi-volume book counts as a book. For example, the two-volume Ballantine Fantasy editions of The Night Land and The Well at the World's End will add up to four books, not two. A forty-volume encyclopaedia set counts as 40 books.
9.Duplicate copies of books certainly do count. The idea is to count books, not "titles."
10.If you're married, it's up to you whether you count all the books in your household or not.
