Blood–brain barrier (BBB) breakdown leading to cerebral edema occurs in many brain diseases―such as trauma, stroke, inflammation, infection, and tumors―and is an important factor in the mortality arising from these con- tions. Despite the importance of the BBB in the pathogenesis of these diseases, the molecular mechanisms occurring at the BBB are not completely und- stood. In the last decade a number of molecules have been identified not only in endothelial cells, but also in astrocytes, pericytes, and the perivascular cells that interact with endothelium to maintain cerebral homeostasis. However, the precise cellular interactions at a molecular level in steady states and d- eases have still to be determined. The introduction of new research techniques during the last decade or so provide an opportunity to study the molecular mec- nisms occurring at the BBB in diseases. The Blood–Brain Barrier: Biology and Research Protocols provides the reader with details of selected morphologic, permeability, transport, in vitro, and molecular techniques for BBB studies, all written by experts in the field. Each part is preceded by a review that emphasizes the advantages and pitfalls of particular techniques, as well as offering much relevant current information. The techniques provided will be helpful to both beginners in BBB research and those more experienced investigators who wish to add a specific technique to those already available in their laboratories.