AGE: 40
OCCUPATION: Mathematician
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 0
PRO: Reclusive Russian genius who solved one of the most significant problems in mathematics, the Poincare Conjecture, but last year declined to accept the Fields Medal, considered equal to a Nobel Prize for mathematics.
CON: Hardly anyone understands the conjecture, let alone the solution.