William P. Thurston died August 21 at the age of 65. After many groundbreaking results in foliation theory, Thurston became a pioneer in the field of low-dimensional topology. Thurston's geometric ideas developed initially in connection with three-dimensional topology have been extremely influential in the last few decades, both in topology and geometry, and in other fields such as group theory and complexity. His geometrization conjecture for 3-manifolds, implying the Poincaré conjecture, was proved by Perelman in 2003. Thurston is
also one of the fathers of geometric group theory. His honors include the Fields Medal (1982), the AMS Book Prize (2005), and the AMS Steele Prize for a Seminal Contribution to Research (2012).