A vast number of diagnostic and therapeutic decisions are based on measuring blood concentrations of molecules, yet most biochemical and pharmacological events actually take place in the tissues. Microdialysis is a key semi-invasive sampling technique to measure in vivo drug penetration to the target site in humans, the method being feasible in virtually every organ. Authored by international experts in this cutting edge field, this book will provide a comprehensive overview of microdialysis and its application for measuring drug distribution in drug development.