The Positive Outcome of Philosophy / The Nature of Human Brain Work. Letters on Logic

The Biology, Physiology and Sociology of Reproduction / Also Sexual Hygiene with Special Reference to the Male

Logic / Deductive and Inductive

Five Stages of Greek Religion

Three Philosophical Poets / Lucretius, Dante, and Goethe

Christianity and Greek Philosophy / or, the relation between spontaneous and reflective thought / in Greece and the positive teaching of Christ and His / Apostles