Mushrooms Demystified by David Arora
is the most comprehensive single book for identifying mushrooms. It has
excellent keys, descriptions, photographs, and writing. It is written primarily with the west coast of the United
States in mind (although species not found in that area are covered).
Less than 10% of the species covered are represented in color
photographs. Mushrooms Demystified covers over 2000 species which is more than any other book you would probably consider purchasing. This book focuses on western species but still is very useful on the east coast. This is by far the best book available for west coast hunters.
How to Identify Mushrooms to Genus III: Microscopic features by David L. Largent is like a users manual for your microscope that focuses on how to use a scope to identify mushrooms. It is written for intermediate to advanced readers and has a lot of information on how to prepare samples and exactly what to look for that is difficult to obtain from any other source.
How to Identify Mushrooms to Genus VI: Modern Genera by T.J. Baroni and David L. Largent Describes all the modern genera and has keys that use macroscopic and microscopic features to place any mushroom in its proper genus. Has great descriptions of exactly what features define the various genera and an excellent mycology glossary. Required reading for all intermediate to advanced mycologists.