How many books are there in the world roughly?

Answer:
A few months ago Google published an estimate (for their Google Books) that, using algorithms to disregard duplicates, almost 130 million books have been published in all of modern history. Their definition of "book" is similar to that required for an ISBN: all new editions and translations, every obscure academic thesis, et cetera.
First answer by Skylarkascending. Last edit by Skylarkascending. Contributor trust: 0 [recommend contributor recommended]. Question popularity: 1 [recommend question].