Since the initial discovery of the claudins, the field of tight junctions and cell polarity has become increasingly energized, mainly due to the fact that the claudins have provided an opportunity to understand the molecular basis of the tight junction function and their tissue specific roles. In Claudins: Methods and Protocols, experts and pioneers in the field provide an extensive collection of techniques involving these tight junction proteins. Written in the highly successful Methods in Molecular Biology(TM) series format, chapters include brief introductions to their respective topics, detailed lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and key tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Claudins: Methods and Protocols serves as an ideal guide for all scientists seeking to further our understanding of this vital area of research.