Oral delivery of Insulin, Second Edition is a complete reference on non-invasive insulin delivery systems, focusing on the prospect of oral delivery of peptides. The chapters in the revised edition present a comprehensive evaluation of the insulin therapy approaches with emphasis on insulin delivery strategies and current advances in engineered insulin delivery systems such as nano/microcarriers, and hydrogels. Including two new chapters, the contents were substantially updated. The first chapter provides an overview of diabetes mellitus, the second chapters covers the technological innovations in the treatment of diabetes, including pancreatic islet cell transplantation, stem cell therapy, ß-cells regeneration and gene therapy incretin therapy, statin therapy, metabolic surgery, and precision medicine approaches. Chapter three covers artificial intelligence and machine learning approaches to manage diabetes, including regulatory aspects. Chapter four explores a wide range of non-invasive and alternative routes of insulin administration. Chapter five covers the challenges and strategies in oral insulin delivery. Chapter six covers the experimental techniques used to develop oral insulin carriers. The next chapter is focused on the use of polymeric nano and microparticles for insulin delivery. Chapter eight focus on the use of lipids and inorganic nanoparticles in insulin delivery. The final chapter provide an overview of current clinical trials on insulin delivery and future perspectives in the area. Oral delivery of Insulin, Second Edition provides an updated and comprehensive overview of the current developments in non-invasive insulin delivery strategies. Pharmaceutical scientists will benefit from the broad coverage. Biomedical engineers can better understand combination approaches to develop new devices. Clinicians can benefit from this information to develop a clear understanding about the research carried out worldwide in the field of oral delivery of insulin including those in the clinical phase.