This well-illustrated volume presents a comparative and historical analysis of dormancy and its role in nature as exemplified by microbial spores. The types of dormancy in bacteria and fungi are compared and related to those found in higher plants and animals. The development of spores is described and illustrated; their comparative morphology is discussed in relation to function. Also, physiological and biochemical aspects of dormant and germinating spores are considered in detail, and an attempt is made to characterize the properties of dormant systems in these terms.