This detailed edition reflects the significant new findings in the components of permeability barriers and how they work in different tissues with a collection of cutting-edge techniques. Chapters explore the formation, maintenance, regulation, and dynamics of permeability barriers in an effort to push the boundaries of the field. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.