I'd have to agree with Kempo_Student, and would like to add

"Pressure Point Karate Made Easy"

By George A. Dillman and Chris Thomas

and

"Humane Pressure point self defense"

By. George A. Dillman and Chris Thomas.

P.P.K.M.E. is a little more youngster oriented, but the techniques and points in the book are good if you're starting fresh
on the whole Kyusho-Jitsu pressure point fighting and tuite-jitsu concepts. Even in our adult class we ask some of the adults to at least glance over it for a nice starting base to everything. I still look over it and I'm a 1rst Dan. "Humane pressure point" is a little more adult-oriented but again makes a good base for you to expand on with the other three books.