Advances in Biological and Medical Physics, Volume III is a collection of papers dealing with the applications of radioactive isotopes, particularly, with the dosimetry of artificial radioactive isotopes, and the kinetics of the turnover of radioactive substances. One paper explains dosimetry in medicine as regards (1) units and absolute dosage rates, and (2) the distribution of radiation in a scattering medium such as the human body. The investigator can use tracers to make individual observations of the behavior of specific molecules in steady state systems. This feature of tracer applications leads to analysis of biological reaction kinetics. Some papers discuss the mechanisms involved in the antigen-antibody reactions, molecular analysis using fast charged particles, x-ray microscopy, ultraviolet microscopy, microspectroscopy, as well as the biological effects of ultrasonic waves. Ultrasonic waves can affect biological material through heat action, mechanical action, or chemical action. One paper suggests that cell disintegration is due to the mechanical effect provoked by cavitation and that cells are probably broken down by the sharp-fronted shock wave resulting from the collapse of cavitation bubbles. The collection can prove beneficial for biochemists, micro-biologists, bio-physicists, cellular researchers, and academicians involved in the study of cellular biology.