I've had trouble figuring out Painter and have several books about it. I think Marilyn's book is the best. Her step-by-step approach is very helpful and I appreciate being able to work on the same images she uses for her illustrations. Her writing style is very clear. She has tons of illustrations showing each artwork as it progresses. The early chapters give you a good understanding of the interface and show you particular strategies for converting photos to paintings.
I like her chapter on portraits the best. She shows how to make hair and eyes that are neither too photographic nor too smeary -- a particular problem for me. The middle chapters have to do with particular types of subjects: portraits, landscapes, flowers. Each of these chapters illustrates new ways of approaching a painting and new techniques. As you work through the chapters you not only see how Painter can be used for these subjects, you also increase the bag of tricks you can use for any painting. The final chapter deals with presentation (mostly border treatments), texturing and printing.