He published many philosophical text-books and treatises, and a number of sermons; but his chief claim to remembrance rests on his elaborate "Grundriss der Geschichte der Philosophie" (Outline of the History of Philosophy, 2 vols, 1866), the 4th edition of which has been translated into English. Erdmann's special merit is that he does not rest content with being a mere summarizer of opinions, but tries to exhibit the history of human thought as a continuous and ever-developing effort to solve the great speculative problems with which man has been confronted in all ages. His chief other works were: "Leib und Seele" (Body and Soul, 1837), "Grundriss der Psychologie" (Outline of Psychology, 1840), "Grundriss der Logik und Metaphysik" (Outline of Logic and Metaphysics, 1841), and "Psychologische Briefe" (Psychological Letters, 1851).