In the last 25 years or so, the importance and frequency of hay fever and asthma from the airborne spores of molds have been largely investigated by American workers, but before this period the Dutch physician, W. Storm van Leerwen, conducted experiments which pointed to molds as a common cause of asthma. The author of this volume is a disciple of Kremer who was associated with van Leerwen. It is thus particularly appropriate that the most complete presentation on this subject is written by such a man. The book describes climates in relation to mold allergy, gives a survey of general mycology, and gathers the findings from all over the world on the presence of mold spores in the open air, in homes, and in special occupational environments. Ample data are given for the preparation of a variety of culture mediums. There are a large number of photographs of molds.