Coherent anti-Stokes Raman scattering (CARS) microscopy permits vibrational imaging with high-sensitivity, high speed, and three-dimensional spatial resolution. We review recent advances in CARS microscopy, including experimental design, theoretical understanding of contrast mechanisms, and applications to chemical and biological systems. We also review the development of multiplex CARS microspectroscopy, which allows high-speed characterization of microscopic samples, and CARS correlation spectroscopy, which probes fast diffusion dynamics with vibrational selectivity.