First Published in 1999. Routledge is an imprint of Taylor & Francis, an informa company.

This is Volume II of ten in the Physiological Psychology series. First published in 1926, this study looks at the areas of pain and pleasure in relation to tension, both unconscious and not, love and hate, a summary of present theories and Freud's theory's on masochism, the pleasure principle and the death instinct in relation to the study's hypothesis.