I just found 'Karate Masters' by Jose Fraguas, published by Unique Publications. The book consists of a collection of interviews (with pictures and some masters favorite techinques) of a wide range of senior karateka.
Among which are Harry Cook, Fumio Demura, Morio Higaonna, Hidetaka Nishiyama, Kenei and Kenzo Mabuni and many others.
The interviews are a fascinating collection of their views on their own training, what they feel represents good karate and their opinions of many issues before us today.
At 338 pages for $19.95 it is a good investment if you wish to listen to those who have walked the walk.