A Forbes article on the 10 most expensive books of 2006 (in the context of rare book auctions) makes this notable observation: “The top 10 list for 2006 includes a surprising number of atlases — five, including three versions of works by Ptolemy.” One of those was a 1477 edition of the Cosmographia that went for the equivalent of $4 million earlier this year.

Previously: Cosmographia Auctioned; Cosmographia Fetches More Than £2.1 Million.