[I'll have much more to say about the Fortsas Hoax at the end of the week as the anniversary approaches again (hint hint), but in the meantime ...]
Walter Klinefelter's The Fortsas Bibliohoax was first printed in 1941 for the Carteret Book Club, and revised and expanded in 1986 by the Press of Ward Schori in a lovely edition of 378 copies. It includes a translated, annotated version of the original Fortsas catalogue from 1840, plus introductory and concluding essays by Klinefelter and a bibliographical discussion of the Fortsas publications by Weber DeVore.
This is by far the best examination and discussion of the Fortsas Hoax in English, and is a must-read for any students of this, one of the greatest literary practical jokes of all time.
[Update: here's the "more to say" I promised - 10 August].