Good Basics
This is a good book. It is heralded by many who practice Kahuna as the classic. I found a seller who sold it under what many are trying to sell it for. While I paid too much, I would recommend anyone interested in Kahuna to get the more reasonably priced book: Fundamentals of Hawaiian Mysticism by Charlotte Berney. She actually covers the basics of Allan P. Lewis' book and in fact quotes him throughout her book.
Good luck with your studies. It is a wonderful study and practice.