A collection of classic, novel, and state-of-the-art methods for the study of cell migration in cultured cells, different model organisms, and specialized cells in normal development and disease. Highlights include basic assays that apply to all cell migration studies in vitro, assays in various model organisms, and assays for cancer cells, endothelial cells, and neurons both in vitro and in animal models. The protocols follow the successful Methods in Molecular Biologya series format, each offering step-by-step laboratory instructions, an introduction outlining the principle behind the technique, lists of the necessary equipment and reagents, and tips on troubleshooting and avoiding known pitfalls.