Photoacoustic tomography (PAT) has been developed for in vivo functional, metabolic, molecular, and histologic imaging by physically combining optical and ultrasonic waves. Broad applications include early-cancer detection and brain imaging. High-resolution pure optical imaging—such as confocal microscopy, two-photon microscopy, and optical coherence tomography—is limited to superficial imaging within the optical diffusion limit (~1 mm in the skin) in scattering tissue. By synergistically combining light and sound, PAT in the form of either photoacoustic computed tomography or photoacoustic microscopy provides deep penetration at high ultrasonic resolution and high optical contrast. PAT is the only modality capable of in vivo imaging across the length scales of organelles, cells, tissues, and organs (or small-animal organisms) with consistent contrast. The annual conference on PAT has become the largest in SPIE’s 20,000-attendee Photonics West since 2010. In addition, compressed ultrafast photography, the world’s fastest camera, will be touched upon.