There is lots of good and some not so good Judo knowledge out there in the form of books. Here is a basic list of some of the better ones I have found. These are all in print and available through on line bookstores or at Powells Books (usually)
This one should be the first one in every one’s library. It is the official publication of the Kodokan and is the best general reference for names and descriptions of techniques, Judo history, philosophy, kata, etc., etc.. Not a lot here on applications of techniques, but that is not the point of this book. It is also available in paperback for a very affordable price.
Kodokan Judo, The Essential Guide to Judo by Its Founder Jigoro Kano. Jigoro Kano. Published by Kodansha USA. ISBN: 9784770017994
This one is the key reference book for all the throws in Judo. It was written by Daigo sensei, 10th dan. It covers all the throws with descriptions of variations on each throw as well. Probably a good idea to get this one while it is still in print.
Kodokan Judo, Throwing techniques. Toshiro Daigo. 2005. Kodansha International. ISBN: 4770023308
Randori and Shiai
Attacking Judo, Katsuhiko Kashiwazaki. 1995. Ippon Books. ISBN: 0951845594
Master Class series (various titles and authors) Ippon Books.
Judo Formal Techniques: A Complete Guide to Kodokan Randori No Kata. Tadao Otaki, Donn F. Draeger . 1990. Tuttle Publishing ISBN: 080481676X
Judo History and Philosphy
Mind Over Muscle: Writings from the Founder of Judo. Jigoro Kano, Naoki Murata. 2006 Kodansha. ISBN: 9784770030153
The Canon of Judo: Classic Teachings on Principles and Techniques Kyuzo Mifune, Françoise White. 2004 Kodansha ISBN: 9784770029799