According to WHO 2012 report 347 million people worldwide have Diabetes. Diabetes mellitus is a serious pathological condition responsible for major healthcare problems worldwide and costing billions of dollars annually. Conventional insulin therapies involve multiple daily subcutaneous injections having many challenges. Hence novel approaches for insulin delivery are being explored. A variety of alternative routes/methods have been investigated to improve systemic insulin delivery. Peroral and nasal insulin administrations have demonstrated good potential for the treatment of diabetes. In addition, pulmonary, buccal, and ocular insulin administration have been shown to decrease serum glucose concentrations. Other methods that have been investigated for their potential in systemic insulin delivery include rectal, vaginal, and uterine routes. This book is helpful to the medical and paramedical students and also researchers who work for the development of novel insulin drug delivery systems and devices.