Physiology and Toxicology of Male Reproduction is a collection of papers that deals with general reproductive biology and specific aspects of reproductive toxicology, pertaining to the male sex. Some papers discuss testicular organization, reproductive toxicity testing systems, and germ-cell genetic toxicology. The use of in vitro systems by investigators to dissect the male reproductive toxicants can lead to a more scientific approach toward hazard assessment and the development of safer drugs and chemicals. Other papers explain the fundamental reproductive biology of the testis, the neuroendocrine system, the epididymis and accessory sex organs, and spermatozoal evaluation. Toxicological aspects cover the toxicological evaluation of the complete reproductive system, testicular morphology, sperm assessment, and germ-cell mutagenesis. One paper describes alternative methods in toxicology—by using new in vitro systems that should reduce or eliminate the need for tests conducted on animals. In vitro methodology embraces other systems such as from subcellular fractions to isolated intact organs. In relation to target-organ toxicity, the researcher can focus using primary cell cultures. This collection will prove helpful to toxicologists, graduate students and researchers in biology, particularly in male reproductive toxicology and fertility testing.