The concept of the perfect medicine as a molecule that goes with high selectivity to the therapeutic target site, does what it needs to do, and is subsequently cleared from the body is especially relevant now. Much of the current costs and post-market safety concerns arise from the inability to achieve adequate concentrations and selectivity in the due course of actually delivering the active drug. Providing an integrated approach, this book presents ways of achieving the desired adequate and selective delivery using the currently available technology in three tool sets: route, regimen, and formulation.