This book contributes the studies and researches done by Dr. S Socransky in the field of oral microbiology. He discovered the pathogenic bacterias in relation to periodontal diseases by various in vivo as well as in vitro studies which became the milestone in diagnosing and treatment planning in periodontal diseases. This book also includes his biography, achievements and his commendable work in the field of Periodontology , which is still a basis for most of the current research as well as clinical work.