Louis Nirenberg was one of the most outstanding analysts of the twentieth century. He was a leader in most of the important developments of the theory of linear and nonlinear partial differential equations, in particular, elliptic equations, hypoelliptic equations and their relation to the theory of several complex variables, topological and geometric methods, and free boundary problems.

Louis Nirenberg had many students and collaborators and inspired generations of mathematicians. His generosity and work will continue to have a profound influence. In an interview in the Notices of the AMS, April 2002, Nirenberg said  "One of the wonders of mathematics is you go somewhere in the world and you meet other mathematicians, and it is like one big family. This large family is a wonderful joy.”

Nirenberg was the Abel Prize recipient together with John F. Nash Jr. in 2015 and received the prize "for striking and seminal contributions to the theory of nonlinear partial differential equations and its applications to geometric analysis.”

He was a frequent speaker and lecturer at Fields Institute workshops and seminars. We looked into our archives, and present you here with an audio file of a Louis Nirenberg lecture on the "Distance Function to the Boundary and Hamilton-Jacobi Equations,” delivered at the Fields Institute on April 6, 2004, as part of the Fields Colloquium in Geometric Analysis.