I've been waiting for this book to arrive! It is a workbook, with exercises and homework in each chapter, to help develop design skills and make art quilts. As the authors say:
Art quilting is both art and quilting - both aspects should be balanced, and yet the definitions of each should be stretched.
The book focuses more on the art in art quilts and assumes that the reader has certain basic quilt making skills. I've just had a quick browse through the book, so I'm not sure yet how much I will learn from it, but I'm going to work through the exercises in my own time. This could be quite an interesting learning experience.