**Anatoly Alexeevitch Karatsuba** (Russian: Анато́лий Алексе́евич Карацу́ба; Grozny, Soviet Union, January 31, 1937 – Moscow, Russia, September 28, 2008) was a Russian mathematician working in the field of analytic number theory, *p*-adic numbers and Dirichlet series.

For most of his student and professional life he was associated with the Faculty of Mechanics and Mathematics of Moscow State University, defending a D.Sc. there entitled "The method of trigonometric sums and intermediate value theorems" in 1966. He later held a position at the Steklov Institute of Mathematics of the Academy of Sciences.

His textbook *Foundations of analytic number theory* went to two editions, 1975 and 1983.

The Karatsuba algorithm is the earliest known divide and conquer algorithm for multiplication and lives on as a special case of its direct generalization, the Toom–Cook algorithm.

The main research works of Anatoly Karatsuba were published in more than 160 research papers and monographs.