It's a discussion of the basic structure of bacteria and viruses and of the varied forms they take. Some simple experiments are included as illustration. The writing lacks style and clarity; it is often confusing, even meaningless (e.g. the statement ""It is said that these microbes can make about 2,500 pounds of protein wastes,"" is offered without noting the amount of the original substance). The authors present a good deal of material, but the explanations are frequently unclear, and terms are used which are not included in the glossary (DNA). The unattractive drawings run from the inadequate to the irrelevant and are poorly captioned.