The blood-brain barrier (BBB) is responsible for the movement of ions, molecules, and cells between the blood and the CNS. This barrier is essential for providing the right environment for healthy neuronal function and also for protecting the CNS from injury and disease. The BBB is made up of three biological components of the brain microvasculature: brain endothelial cells (BECs), astrocyte end-feet, and pericytes (PCs). BECs are essential components of the BBB, responsible for protecting the brain from pathogens while also limiting the flow of circulatory factors. Astrocytes, which are five times the number of neurons in the CNS, provide simple structural and nutritional support for neurons and also contribute to the composition of the BBB. Pericytes play an essential role in angiogenesis, vascular remodeling, vascular tone, and BBB development. Several neurologic diseases such as stroke and neuroinflammatory disorders are affected by the BBB dysfunction. This book presents researches and studies performed by internationally acclaimed experts on the role of blood-brain barrier. It will serve as a valuable source of reference for graduate and post graduate students.