The motive behind the publication of this handbook has been the scarcity of easily accessible literature on ruminant health in the Indian region particularly in the field veterinarians and animal scientists. Most often, scientific literature published in journals is available in libraries of the Universities and research institutions which are not easily accessible to workers in the extension services. Therefore, this handbook is an attempt to extend the accumulated knowledge on diseases of ruminants to field workers. It is also suitable for students undertaking veterinary or small ruminant health-related studies in the region in addition to those who are engage in Research or M.Sc. studies in Biosciences particularly Parasitology. The handbook is presented in easily understandable language. Emphasis has been laid on the most commonly reported helminthic, protozoan and arthropod diseases of ruminants and other related diseases of common occurrence.