BOOK is primarily prepared for field veterinarian, who have to attend the out breaks in lack of facilities as well as any guidance needed for diagnosing the disease in out breaks. they can reach certain conclusions by following the techniques detailed in this book. This book is of value for junior disease investigator officers who may be involved in field work. This is also of great value to undergraduate and postgraduate students who are being initiated in disease investigation in infection related diseases. The text is also useful to educated farmer who can assist the veterinarians by collecting information for them. it would be good for disease investigation laboratories of field training centres for veterinarians. Up to date information has incorporated for the benefit of researches and field workers.