Mirror Symmetry and the Strominger-Yau-Zaslow conjecture

This survey was written for the Current Developments in Mathematics conference, 2012, and is an updating of my article “The Strominger-Yau-Zaslow conjecture: From torus fibrations to degenerations,” in the Seattle 2005 proceedings. We trace progress and thinking about the SYZ conjecture since its introduction in 1996. We begin with the original differential geometric conjecture and its refinements, and explain how it led to the algebro-geometric program developed by myself and Siebert. After explaining the overall philosophy, I explain how recent results fit into this program.