Abstract
We review the relation between Chern-Simons gauge theory and topological string theory on noncompact Calabi-Yau spaces. This relation has made possible to give an exact solution of topological string theory on these spaces to all orders in the string coupling constant. We focus on the construction of this solution, which is encoded in the topological vertex, and we emphasize the implications of the physics of string/gauge theory duality for knot theory and for the geometry of Calabi-Yau manifolds.