Biological control of agricultural pests around the world and especially in Egypt may help to reduce the environment pollution by insecticides in addition to save costs for controlling it. The book aims to clear the important role of mites in suppressing number of harmful insects by survey the bio-relationships between mites and economic insects at six Egyptian governorates during three successive years. These relations classified into six categories. Results revealed eighty-two mite species belonging to fifty-five genera associated with forty two insect species belonging to eight insect orders. Also, taxonomical studies for new mite species and finally, biological studies for two common predacious mites in Egypt to throw light on their efficiency in Integrated Pest Management programmes (IPM).