Retired professors Carranza (dentistry, UCLA) and Shklar (oral pathology, Harvard School of Dental Medicine) each have some 50 years of experience in dentistry. Their historical look recognizes periodontology's direct links to the medical sciences, biology and technology, and significant developments in these fields, particularly in the 19th and 20th centuries. It provides practitioners, scholars and students an opportunity to understand and appreciate their predecessors and the origins of their profession. Illustrated in b&w.