This book features contributions from experts in cell biology, genetics, neurobiology, immunology and structural biology. The unifying element is that they all study processes of cell shape change and motility. Several key questions in this field of research are discussed: What are the organising principles behind cell shape change? Are there master switches present in every cell type? How are extracellular signals interpreted by the cell in order to activate intracellular mechanisms? What is the influence of the extracellular matrix on cell movement and internal signalling pathways? How do pathogens subvert cellular systems in order to stimulate or block their uptake? The book addresses all of these important questions. Data are presented on the key proteins that regulate cell shape: the GTP binding proteins of the Rho family. There are also extensive discussions of the potential applications of the data to clinical problems, particularly that of cell motility in cancer.