This chapter presents the anatomy, embryology and pathophysiology of the development of peritoneal adhesions. The author draws on a wealth of experimental research knowledge and is himself a leader in current high-level peritoneal research. Embryologically, the body cavities and the descensus testis are described; the pathophysiology of the peritoneum is discussed and finally the pathophysiology of the development of peritoneal adhesions is described on the basis of the latest research findings.