This textbook survey deals mainly with the observational and experimental work comprehending formal psychological accounts of sensory reception and the interpretation of external impressions at higher mental levels. The first section provides what is significant for neuropsychiatric groundwork in its general accounts of the impairment of conscious states in mental disease; amnestic fugues; double and multiple personality; cerebral pathology and mental life; theories of cerebral function; conditioned reflexes; organization within the nervous system; the organism and the nervous system, etc. Other main textual divisions are entitled Landmarks in the Theory of Perception; The Psychology of Perception;