I enjoyed this book. It is extremely clear and very helpful. Every step explained in words and pictures. It is the most straightforward instruction book on any subject that I have ever read.
The author is Tricia Yu, not William Chen, as Amazon has it catalogued.
There is a quotation from William Chen on the cover of the book, which may have misled the cataloguers.

This is a very good book for water colour painters who have learnt the basics and wish to stretch themselves. It contains about 130 interesting landscape photographs, together with a discussion on a possible approach to painting them by a well known painter and the resulting demonstration.
My personal criticisms are firstly the over frequent use of guache in the suggestions, and secondly the large palette used, rather than resorting to the mixing of primary transparent colours. The use of Alizarin Crimson should be replaced by a lightfast equivalent.
But it is an excellent source book for painters returning to painting and for first time learners who have tackled Jack Reid's books, for example. Many of the demonstrations are first rate and almost all of the photographs are very stimulating.