This book is first English edition from 1975. After the monumental work of Max Doerner, this book is more modern view and includes acrylic grounds and paints. Kurt Wehlte also gives information about mixed technique. The reprints after this hard cover edition have been somehow abbreviated and the font have been shrieked to fit in 350 - 400 pages instead of 800 pages and are missing the photographs. Since is 40 years old some technical abbreviations for the pigments (like PY37) are missing but the chemical composition is given. It is the only book comparable to inspirational work of Max Doerner.
Dix and Wehlte's book is basically an encyclopedia of painting. I expect to spend a lot of time
looking at it over the next few years. It is not a quick "how to" book.