"Miyamoto Musashi, His Life and Writings" - Kenji Tokitsu
(An astonishing investigation of how a true master develops himself.)
"Effortless Combat Throws, Principles and Analysis" - Tim Cartmell
(especially the first two chapters; important for all martial arts)
"Xing Yi Nei Gong" - Wan Ji Wu (translated Cartmell and Miller)
"Xing Yi Quan Xue" - Sun Lu Tang
"Championship Fighting" - Jack Dempsey
( available w/illustrations at
http://www.freecirclefighting.com/jdbook.pdf )
"The Record of Linji" - Thomas Yuho Kirchner and Ruth Fuller Sasaki
(You've toughened your muscles and hands; now, toughen your mind)
"On Killing" - Col. Dave Grossman
"Hara, the Vital Center of Man" - Karlfried Graf vonDurckheim
"Light On Yoga" - B.K.S. Iyengar
(Not a martial arts book, you say? Apparently, you've never studied with Mr. Iyengar.)
"The Mixed Martial Arts Instruction Manual: Striking" - Anderson Silva
(For my money, more detailed and valuable than Fedor's book.)
I like the "Flow" book as well, and I know how to pronounce the author's name; so, that's a plus.