Bjorn Poonen

Bjorn Mikhail Poonen (born 27 July 1968 in Boston, Massachusetts) is a mathematician, four-time Putnam Competition winner, and a Distinguished Professor in Science in the Department of Mathematics at the Massachusetts Institute of Technology. 
His research is primarily in arithmetic geometry, but he has occasionally published in other subjects such as probability and computer science.
He has edited two books, 
and his research articles have been cited by approximately 1,000 distinct authors. 
He is the founding managing editor of the journal "Algebra & Number Theory", and serves also on the editorial boards of "Involve" and the "A K Peters Research Notes in Mathematics" book series.
Education.
Poonen is a 1985 alumnus of Winchester High School in Winchester, Massachusetts. In 1989, Poonen graduated from Harvard University with an A.B. in Mathematics and Physics, summa cum laude. He then studied under Kenneth Alan Ribet at the University of California, Berkeley, completing a Ph.D. there in 1994.
Academic positions.
Poonen held postdoctoral positions at Mathematical Sciences Research Institute and Princeton University and served on the faculty of the University of California, Berkeley from 1997 to 2008, before moving to MIT.
He has also held visiting positions at the Isaac Newton Institute (1998 and 2005), the Université Paris-Sud (2001), Harvard (2007), and MIT (2007).