The use of plants for medicinal purposes date back a long time ago and probably happened when primitive people noticed that animals like chimpanzees partake of certain plants when they got sick. It has been reported that even around some 3000 years B.P., human beings were aware of the medicinal properties of plants. A number of important modern pharmaceuticals have been derived from, or are plants used by indigenous people. Modern drugs like aspirin, atropine, ephedrine, digoxin, morphine, quinine, reserpine and tubocurarine are some examples, which were originally discovered through observations of traditional cure methods of indigenous peoples. Bangladesh has also a rich history of traditional medicinal practices (alternately known as alternative or complementary medicine). Besides the established systems of Ayurveda and Unani, traditional medicinal practitioners in Bangladesh (known variously as Kavirajes or Vaidyas) follow their own system, which can be termed as 'folk medicinal system'. Various tribes in Bangladesh also have their medicinal systems, which can be considered as variants of folk medicine. In folk or tribal medicine, each Kaviraj or tribal medicinal practitioner has his or her own unique formulations of medicinal plants based on partly his or her own experience, and partly on the basis of plants growing in his or her own vicinity. Documentation of medicinal plants is important not only to identify the medicinal plants of a country but also to initiate further research, which may lead to discovery of new drugs. Such discoveries are important because of the emergence of new diseases like Ebola or AIDS and because of the emergence of existing drug-resistant vectors. Bangladesh is lacking in this respect for there is not much data available on medicinal plants of the country and their uses. This volume and subsequent volumes will be an attempt to fill up this gap on folk and tribal medicinal practitioners.