Refreshingly, this is not another agonizingly detailed trip through all the menus and buttons of the application. The book is focused on (gasp) actually making paintings. With the furnished data files and friendly writing, Rhoda Grossman walks you through the creation of several paintings, all the while nudging you to add your own personality to the work.
I've bought several Painter books over the years, and this is easily the best. You can learn the mechanics of the program from the help included with Painter. Grossman's book gets you going on the actual creative work--which is probably why you bought Painter to begin with.