The text book Lead toxicity is theory concerning the lead problem in aquatic environment and its impact on a particular fish organism showing alterations in carbohydrate metabolism, metabolites and enzymes after a period of exposure time and later the effected which has been transferred to lead free water showing gradual recovery in the altered enzymes and metabolites. Amongst different environments, aquatic environment is the serious sufferer of the damage caused by the input of anthropogenic pollutants.These substances are generally discharged into the environment as a result of industrial processes and pose a problem because they are toxic and tend to accumulate in organisms. Minimata disease caused by the consumption of mercury contaminated shellfish and finfish taken from Minimata Bay in Japan, and Itai-Iatai disease, caused by the consumption of food contaminated by cadmium in Japan (Ui 1972) have increased the awareness of toxic effects of the heavy metals on human beings and that has Prompted to take steps for their control.Authors believe that this book will surely serve the purpose of those for whom it has been written.