Synopsis India is designated as one of the mega diversity countries in the world wherein the Western Ghats Region is considered as 'Hot Spot' rich in biodiversity and endemic species. The Agastyamalai region located at the southern part is well-known for biodiversity and medicinal plants richness as a Centre of Species Diversity, designated by the World Conservation Union (IUCN). The Kalakkad-Mundanthurai Tiger Reserve comprising a major part of the Tirunelveli district and a minor part of Kanniyakumari district situated in the Agastyamalai region. The tribals, Kanis or Kanikkars are inhabited only in the Agastyamalai region. The book contains ethnobotanical data for 352 plants that are used to cure 191 diseases. Of them, new uses of plants which are not recorded in earlier literature include 299 plants used to cure 169 diseases including 47 endemic and threatened plants. The work exposes the indigenous knowledge of the Kanis. The leads given in this book are useful to discover and develop drugs after throughput scientific screening. The book is the first of its kind dealing with the knowledge of Kanis in depth.