This is a comprehensive reference source on 18th-century authors writing in the English language about philosophical ideas and issues. It features authors taken from 1689 through to the mid-19th century, the period beginning with John Locke and ending with Dugald Stewart. The word "philosophical" is used in a wide, 18th-century sense. Therefore, the "Dictionary" includes epistemology, ethics, aesthetics, education, politics, rhetoric, science, medicine, biology, geology, chemistry and theology. The book includes short biographies of the writers, and expositions and analyses of their doctrines and ideas.