The movement and growth of cells are critical for normal physiological processes, and--when perturbed--can result in negative outcomes such as tumor formation. Understanding how live cells function is therefore invaluable for molecular and cellular biologists, and advanced techniques to visualize cells in action are of great importance. The current issue of Cold Spring Harbor Protocols offers two freely accessible protocols: one for inserting 'reporter' proteins into cells to monitor what's going on inside, and another for maintaining the cells under a microscope for long-term observation. Release