This completely revised second edition provides all the information necessary to identify mushrooms in the field in the midcontinental region of Iowa, Illinois, Nebraska, Missouri, Minnesota, South Dakota, and Wisconsin: the tallgrass prairies and the western parts of the eastern deciduous forests. The first edition has been improved in significant ways. The authors have updated scientific names, added photos where there were none and replaced poor photos with better ones, improved the keys, added some species and deleted others, added a section on truffles, and annotated the bibliography. There were originally 224 species; now there are 248. Some of the new photos--125 in all--serve as a second photo for a species, where it is helpful to show details that cannot be viewed in a single photo. The authors describe each species' cap, gills, stalk, annulus, and season when it is most likely to be seen as well as such characteristics as edibility and toxicity. In their detailed and lively introduction they discuss the economic and environmental aspects of fungi, basic mushroom biology, nomenclature, edibility and toxicity, and habitats and time of fruiting. Most important are the keys, which lead the dedicated reader to the major groups of fungi included in this guide. The section on mushrooms includes keys to their genera in addition to the species within each family discussed, and each of the subsequent sections has a key to the genera and species except where so few species are discussed that a key is not necessary. The volume also includes a glossary and two bibliographies, one with general and one with technical references. Through their detailed technical descriptions and captivating color photos the authors convey their passionate fondness for these diverse and colorful organisms, whose mysterious appearances and disappearances have long made them objects of fascination.