Mortimer Jerome Adler (December 28, 1902 – June 28, 2001) was an American philosopher, educator, encyclopedist, and popular author. As a philosopher he worked within the Aristotelian and Thomistic traditions. He lived for long stretches in New York City, Chicago, San Francisco, and San Mateo, California. He taught at Columbia University and the University of Chicago, served as chairman of the Encyclopædia Britannica Board of Editors, and founded his own Institute for Philosophical Research.