Since the full functionality of any given protein can only be understood in terms of its interaction with other, often regulatory proteins, this unique reference source covers all relevant protein domains, including SH2, SH3, PDZ, WW, PTB, EH, PH and PX. Its user-oriented concept combines broad coverage with easy retrieval of essential information, and includes a special section on Web-based tools and databases covering protein modules and functional peptide motifs. Essential for the study of protein-protein interactions in vivo or in silico, and a prerequisite for successful functional proteo.