The document provides an introduction to the Ayurvedic concept of Vyadhi (disease). It discusses the etymology and definitions of Vyadhi, as well as synonyms. Various classifications of Vyadhi are described based on factors like prognosis, intensity, location, causes, and site of origin. Single-fold, two-fold, and three-fold classifications are presented, differentiating types of Vyadhi according to these factors. The document serves as an overview of the fundamental Ayurvedic understanding of the nature and categories of disease.