Leonard Mlodinow is an American theoretical physicist, mathematician, screenwriter, and author. In the field of physics, he is noted for his work on the large N expansion, a method of approximating the spectrum of atoms by considering an infinite-dimensional version of the problem, as well as his contributions to the quantum theory of light inside dielectrics.

He is also a successful author for the general public, with five of his books reaching the status of New York Times best-sellers. Among his notable works are The Drunkard's Walk: How Randomness Rules Our Lives, a New York Times notable book and shortlisted for the Royal Society Science Book Prize; The Grand Design, co-authored with Stephen Hawking, which discusses the irrelevance of invoking God to explain the origins of the universe; War of the Worldviews, co-authored with Deepak Chopra; and Subliminal: How Your Unconscious Mind Rules Your Behavior, which won the 2013 PEN/E. O. Wilson Literary Science Writing Award.

Leonard Mlodinow is also known for his public lectures and media appearances on various programs including Morning Joe and Through the Wormhole. He notably debated Deepak Chopra on ABC's Nightline.