This textbook introduces details of Pharmacological and Toxicological Screening Methods -I in a systematic way with exercises at the end of each chapter. Unit 1 introduces Laboratory and Transgenic animals and Good Labouratory Practices. Units 2-5 detail about In - Vivo and In-Vitro pre-clinical screening methodsfor drugs used in CNS , ANS , Respiratorysystem , Reproductive system, Gastro-intestinal system , Cardiovascular system , Anti-cancer agents and Immunomodulators. Unit 5 explains the General Principles of Immunossay.