Applied genetic research, genetic toxicology and mutation research investigate the mutagenicity of chemicals and other agents. Permanent mutation in genes and chromosomes can be induced by a plethora of agents, including ionizing and nonionizing radiations, chemicals, and viruses. Among the aspects discussed in Advances in Mutagenesis Research are: 1. The understanding of the molecular mechanisms leading to mutations, and 2. the prevention of a thoughtless introduction of mutagenic agents into the environment.