Book excerpt: Recent applications of new molecular and cellular techniques have greatly expanded our knowledge of how toxicants produce their adverse effects. As a consequence, the time has come for a substantial revision of Professor Ernest Hodgson's classic reference in the field. This Third Edition now contains updated overview chapters on immunochemical and molecular techniques. It also features entirely new chapters covering such crucial topics as immunotoxicology, cutaneous toxicology, reproductive and developmental toxicology, and molecular epidemiology.