Simply put, this fungal guide is rather dated since so many mushrooms have been reclassified since it was written. For example the various chanterelles of California were not known at the time it was published. The section on Russulas is quite out of date as it seems at least a third to half the names are no longer valid. I should also mention that this book, in the best of times, is not easy to use without a microscope. The book is an interesting reference for the curious, but certainly not a current field guide. I like the humor in the book and the honesty on the part of the author that there is not enough space to be thorough on various groups.