Marc D. Bishop, Okinawan Karate: Teachers, Styles and Secret Techniques, Tuttle Publishing, 1999

From their roots in China, the historical development of each karate and kobudo system--Okinawa's greatest cultural export--is presented here via the teachers who formulated them into the many fragmented styles practiced today throughout the world.
Okinawan Teachers, Styles and Secret Techniques , written by one of the foremost writers on Japanese martial arts, specifically Okinawan, presents important elements of the fighting arts as a whole, along with the "ins" and "outs" of health-oriented training and the "secrets" of developing intrinsic energy ( ki ) circulation.
This updated and revised edition reflects the rapid changes that have occurred within the Okinawan martial arts. Features in this Okinawan karate book include historical tables and vital striking point charts, as well as detailed historical information and an account of the contemporary karate, kobudo, and ti (or te) scene in Okinawa.
Source: https://www.goodreads.com/book/show/88480.Okinawan_Karate