This volume contains the proceedings of the virtual AMS Special Session on Harmonic Analysis, held from March 26-27, 2022. Harmonic analysis has gone through rapid developments in the past decade. New tools, including multilinear Kakeya inequalities, broad-narrow analysis, polynomial methods, decoupling inequalities, and refined Strichartz inequalities, are playing a crucial role in resolving problems that were previously considered out of reach. A large number of important works in connection with geometric measure theory, analytic number theory, partial differential equations, several complex variables, etc., have appeared in the last few years. This book collects some examples of this work.