Most sourdough cookbooks fall into one of two camps: The hedgers, who add baking powder or commercial yeast to all their recipes, presumably just in case their starter doesn't perform as desired; and the purists, who never add extra leavening to anything. This book straddles the line nicely, providing both kinds of recipes sorted into sections to suit your mood and the amount of time you have available for baking. There is a great chapter explaining how sourdough works and why you need so much time to bake using it, and another devoted to the ins and outs of adapting sourdough for bread machine use. There is a section of recipes using commercial yeast and the regular bread machine cycle, a section using wild yeast and the bread machine cycle, and a section of wild yeast recipes using only the dough cycle.
The authors tell you approximately how many hours each step will take, which is very helpful when planning your baking, but I will confess to being somewhat turned off by the fact that they describe their starters in terms that seem to be specific to Ed Wood's dried starters for sale ('fast', 'slow', 'Russian', 'Austrian', etc.)
Aside from the odd spelt and kamut bread recipes, there are a lot of rye recipes in this book, pitas and rolls, a selection of bread flavors from around the world, and the very best plain sourdough French bread I have ever made. This book is a great addition to any sourdough baker's collection.