Painting Sunlight and Shadow with Pastels: Essential Techniques for Brilliant Effects
I love this book!
It goes through the basics. It covers shadows and lighting in every possible scenario. Shadows are often a difficult and debatable subject between artists.
There aren't a lot of easy to read books about shadows, dedicated entirely to the wonderful medium of pastel. I like Maggie's approach and have learn a lot from her book. I love just looking at her paintings, as though the book is a coffee table, not just an educational one.
She has produced a good book, full of information for the beginner and more advance artist alike.