While the scientific classifications and descriptions have been strictly followed, the language has been simplified—with no sacrifice of scientific accuracy—that this volume may be fully adapted to popular use. Professor Peck has given his valuable assistance in the identification of many species, all that were difficult or obscure having been submitted to him, and the writer is deeply indebted to him for many and long-continued courtesies, aiding in study and in the preparation of this work. Several new species have been found by the writer, the greater part of excellent food value. He preferred that these should be named, described and placed in their proper genus and section by Professor Peck, believing it to be best for the discoverers of new species to defer to one whose vast experience enables him to name and classify in accordance with the demands of American species. Where a species is vouched for as edible, it has been personally tested by the author and his willing undertasters up to eating full meals of it, or at least beyond all doubt as to its safety. Where others have eaten species which he has not had the opportunity to test, their names and opinions are given. When species heretofore under the ban of suspicion are in this volume, for the first time, announced to be edible (there are many of them), personal tests have not been considered sufficient, as idiosyncrasy might have affected the results. Others, at the writer’s request, have eaten of the species until their innocence was fully established. In some cases, where the reputation of the fungi eaten was especially bad, scientists of note have made elaborate and exhaustive physiological tests of their substances, and in every instance confirmed the human testing. While species which contain deadly poisons are few, their individuals are produced in great number. Nicety in distinguishing their botanic variance from edible species closely resembling them is necessary. No charm will detect the poison. Eating toadstools before their certain identification as belonging to edible species, is neither bravery nor common sense. The amateur should go slow. The question often asked is: By what rule do you distinguish between edible and poisonous mushrooms? The answer usually surprises the questioner—there is no general rule. All such rules which have been given are false and unreliable. The quality of each was learned, one at a time. Sweet and sour apples alike grow on large and small trees, may be red or green, large or small, oblong or globular, and no visible appearance gives the least clue to the quality. In a few genera certain rules may be applied, as in Clavaria--all not bitter or tough are edible. But such generalizations are each limited to its own genus.