In this lively book, John Macnamara shows how a number of important thinkers through the ages have approached problems of mental representation and the acquisition of knowledge. He discusses the relevance of these approaches to modern cognitive psychology, focusing on central themes that he believes have strongly influenced modern psychology. This is not a neutral historical survey, but a vehicle for Macnamara's compelling and provocative arguments on the relevance and worth of certain aspects of psychological and philosophical thought.

The historical figures discussed are quite varied-from Plato to Thomas Jefferson to Sigmund Freud-and include numerous Christian philosophers such as Augustine and Thomas Aquinas. The book assumes no previous background in the subject matter; Macnamara often simplifies abstract concepts via homespun examples (many using his beloved dog, Freddie). This is a quirky, engaging book, as well as the last work by a highly influential figure in cognitive psychology.