The growing population in the world requires an increase in the food production and intensive health care systems. Usage of chemical pesticides is inescapable for managing insects in agriculture, disease transmission, weeds and harmful microbes. Due to the current concern about the environment, checking and estimating pesticide residue has become very important in crop plants, soil, food, water and other ecosystems. This book discusses new innovative trends to identify pesticide residue in animal origin food, crop plants and fishes. It also expands on the various advanced extraction methods used in preparing samples for residue analysis. Aside of residue assays, metabolism and degradation of pesticide compounds like chlorpyrifos, fenamophos, heptachlor, pirimiphos and other organic pesticides have also been discussed within the book.