Richard Peter Stanley (born June 23, 1944 in New York City, New York) is the Norman Levinson Professor of Applied Mathematics at the Massachusetts Institute of Technology, in Cambridge, Massachusetts. He received his Ph.D. at Harvard University in 1971 under the supervision of Gian-Carlo Rota. He is universally recognized as a leading expert in the field of combinatorics and its applications to a variety of other mathematical disciplines. He is well known for his two-volume book Enumerative Combinatorics (1986–1999), a far-reaching and authoritative treatise on enumerative methods that is widely regarded for its elegant exposition, usefulness as a reference, and creative exercises. (Perhaps the most famous exercise is in volume 2, where readers are asked to prove that 66 different definitions of the Catalan numbers are equivalent.) He is also the author of Combinatorics and Commutative Algebra (1983) and well over 100 research articles in mathematics. He has served as thesis advisor to more than 45 doctoral students, many of whom have had distinguished careers in combinatorial research.