The Peritoneal cavity (PC) is the key metastatic site for intra-abdominal malignancies (e.g., GI tract and rectal cancer). PC sites can be used to target several other diseases where lymphatic drug delivery is desired without dumping large amounts of the drug. Until recently, it was thought that treatment with curative intent was impossible but that was challenged by the introduction of cytoreductive surgery (CRS), heated intraperitoneal chemotherapy (HIPEC), and PIPAC (pressurized intraperitoneal aerosol chemotherapy). Recently, a growing number of preclinical and clinical studies advocate intraperitoneal (IP) chemotherapy as an alternative post-operative therapy for cancer. Although their effectiveness has been proven both experimentally and clinically, there is still little understanding of the role of drug delivery systems in targeting drugs in the intraperitoneal (IP) cavity. There are two main challenges posed to such therapies 1) the complexity of IP cavity and 2) the drug transport dynamics e.g., the residence time of small molecular weight drugs, the fate of delivery systems (both nano and micro), etc. The present book is a link between pharmaceutical scientists (drug formulators), clinicians, and toxicologists. This book also provides a new perspective to researchers to divert or guide their research in an optimal way. Exploring Drug Delivery to the Peritoneum serves as a platform for upcoming technologies especially in the medical devices sector to face up and show potential in delivering drugs to IP cavity. It is a chance for commercial partners like insurance companies and the pharma industry to explore the old administration route in a new way.