Jordan Ellenberg is an American mathematician, writer and professor whose research focuses on number theory and algebraic geometry. Raised in Potomac, Maryland, he competed for the United States three times at the International Mathematical Olympiad, winning two gold medals and one silver. He studied mathematics at Harvard University, completed a master’s degree in fiction writing at Johns Hopkins University and returned to Harvard for his PhD in mathematics.

After postgraduate work at Princeton University, Ellenberg joined the University of Wisconsin-Madison, where he became the John D. MacArthur Professor of Mathematics. His research has explored connections between number theory, algebraic geometry and algebraic topology. Alongside his academic work, Ellenberg has written extensively for general audiences. His books include the novel The Grasshopper King, the bestselling How Not to Be Wrong and Shape, which examine mathematical ideas and their applications beyond specialist research.