File:Past-master-book-cover.jpg

Summary
low res scan of 1968 Ace paperback first edition of Past Master for use in illustrating article about that very book, retrieved from http://www.isfdb.org/cgi-bin/pl.cgi?25691. This image meets fair use criterion as it is a low resolution image of a book cover, which is the only image used in the book's article; Free replacements are impossible, and it has no commercial effect on Ace books, as Ace Books has ceased to publish Past Master (it is now published on-demand by Wildwood Press).