Abstract: I will first introduce the problem of the BCS-BEC crossover in a Fermi gas with arbitrary interactions and describe the progress in realizing these ideas in experiments with ultracold atomic gases. I will then discuss three questions: (1) How quantum fluctuations about the mean field state impact observable properties in the crossover; (2) How the vortex and core states evolve from the BCS to the BEC limits; (3) Why the most strongly interacting regime at unitarity leads to the most robust superfluid in the entire crossover.