RITTER, HEINRICH (1791-1869), German philosopher, was born at Zerbst on the 21st of November 1791, and died at Göttingen on the 3rd of February 1869. He studied philosophy and theology at Göttingen and Berlin until 1815. In 1824 he became extraordinary professor of philosophy at Berlin, whence he was transferred to Kiel, where he occupied the chair of philosophy from 1833 to 1837. He then accepted a similar position at the university of Göttingen, where he remained till his death. His chief work was a history of philosophy (Geschichte der Philosophie) published in twelve volumes at Hamburg from 1829 to 1853. This book is the product of a wide and thorough knowledge of the subject aided by an impartial critical faculty, and its value is demonstrated by the fact that it has been translated into almost all the languages of Europe. He wrote also accounts of ancient schools of philosophy, the Ionians, the Pythagoreans and the Megarians. Beside these important historical works, he published a large number of treatises of which the following may be mentioned: Versuch zur Verständigung über die neueste deutsche Philosophie zeit Kant (1853); Die christliche Philosophie bis auf die neuesten Zeiten (2 vols., 1858-59), a work which supplemented the Geschichte; Abriss der philosophischen Logik (1824); Ueber das Verhältnis der Philosophie zum Leben (1835); Historia philosophiae Graeco-Romanae (in collaboration with Preller, 1838; 7th ed., 1888); Kleine philosophische Schriften (1839-40); System der Logik und Metaphysik (1856); Encyklopädie der philosophischen Wissenschaften (1862-64); Ernest Renan, uber die Naturwissenschaften und die Geschichte (1865); Ueber das Böse und seine Folgen (1869). Of these latter, the one best known in England is the History of Greek and Roman Philosophy, which, by reason of the excellence of its arrangement and its judicious quotations and notes, is almost indispensable to the student of ancient philosophy.