Leonard S. Peikoff (born October 15, 1933) is a Canadian-Americanphilosopher. He is an author, a leading advocate of Objectivism and the founder of the Ayn Rand Institute. A former professor of philosophy, he was designated by the philosopher Ayn Rand as heir to her estate. For several years, he hosted a nationally syndicated radio talk show.

Peikoff was born in Winnipeg, Manitoba, Canada, to Samuel Peikoff, MD, a surgeon, and his wife Bessie, a band leader. He attended the University of Manitoba from 1950 to 1953 as a pre-med student, but following his early discussions with Rand, he transferred to New York University to study philosophy, where he received his BA, MA and PhD degrees in philosophy in 1954, 1957 and 1964, respectively. His doctoral dissertation adviser was the noted American pragmatist philosopher Sidney Hook, and his dissertation dealt with the metaphysical status of the Law of Non-Contradiction. He taught philosophy for many years at various colleges.

Peikoff first met Ayn Rand through his cousin Barbara Branden (then Barbara Weidman) in California when he was 17. He reports that this meeting with Rand made him aware of the profound importance of philosophy. When Rand later moved to New York City, Peikoff decided to study philosophy at New York University. While studying at NYU, he frequently discussed philosophy privately with Rand in depth across a range of issues.

Ayn Rand ( /ˈaɪn ˈrænd/; born Alisa Zinov'yevna Rosenbaum, February 2 [O.S. January 20] 1905 – March 6, 1982) was a Russian-American novelist, philosopher, playwright, and screenwriter. She is known for her two best-selling novels The Fountainhead and Atlas Shrugged and for developing a philosophical system she called Objectivism.

Born and educated in Russia, Rand moved to the United States in 1926. She worked as a screenwriter in Hollywood and had a play produced on Broadway in 1935–1936. After two initially unsuccessful early novels, she achieved fame with her 1943 novel The Fountainhead. In 1957, she published her best-known work, the philosophical novel Atlas Shrugged. Afterward she turned to nonfiction to promote her philosophy, publishing her own magazines and releasing several collections of essays until her death in 1982.

Rand advocated reason as the only means of acquiring knowledge and rejected all forms of faith and religion. She supported rational and ethical egoism, and rejected ethical altruism. In politics, she condemned the initiation of force as immoral and opposed all forms of collectivism and statism, instead supporting laissez-faire capitalism, which she believed was the only social system that protected individual rights. She promoted romantic realism in art. She was sharply critical of the philosophers and philosophical traditions known to her besides Aristotle.