Plants are a part of our everyday life and have always been. Ethnobotany is the study of the complex relationship between humans and the plant world found in their surroundings. This discipline has a long history of academic research all over the world. Ethnobotanical research includes the use of plants in all aspects of life, e.g. specific customs, religious beliefs, food, medicine, fibres, and other cultural or economic aspects. The use of certain species of plants can give important information on the complex interaction of people and plants in the past, the present, and the future. In some cases, even the linguistic analysis of specific local plant names can be used to inform us about past land use or specific vegetation features. This chapter provides an overview of ethnobotany and how ethnobotanical work can be done, also referring to central handbooks on the subject. We explain some of the most important methods on how to study ethnobotany in historical contexts and in present communities, including different kinds of interviews. The chapter also highlights the importance and contributions of ethnobotany in undertakings based in Historical Ecology by gaining additional information on local communities in past and present.