Rapamycin is a macrocyclic natural product involved in various biological and pharmacological processes including antifungal, immunosuppressive, antitumor, neuroprotective and antiaging activities. In this book, the authors present current research in the study of the effectiveness, safety and drug interactions of rapamycin. Topics discussed include mTOR inhibitors in chronic liver diseases and cancer; rapamycin analogs temsirolimus and everolimus in the treatment of renal cancer; rapamycin control of multiple signalling pathways involved in cancer cell survival and drug resistance to rapamycin through elevated phospholipase D activity.