Why not Vermillion?

The Aegean Park Press just made my day by publishing M-30, Japanese Diplomatic Secrets as I have been hunting for over a year now in hopes of finding the algorithm for the purple, jade and coral ciphers used in WWII by the Japanese. If I ever actually find it I'll write Crypto::Purple/Coral/Jade for CPAN. It contains nearly 1200 pages on CD-ROM in PDF format. Apparently it was authored by the same guy who published the classic book about the Black Chamber but was censored from being published before now. The Man Who Broke Purple is an excellent read if you're interested in Purple but be sure to get an edition with all the pages since some of the early printings had an error and are missing the last 50 or so.

Of course, they have oodles of other cool books on a wide range of cryptologic and intelligence topics too. If credit cards could groan, mine would be screaming. :)