Introduction and guidebook to those pioneers, most of them surgeons, who attempted to help their patients by extending the boundaries of their own knowledge and experience. Before Pasteur and Lister, surgery from the oesophagus to the anal canal was extremely dangerous due to ignorance of the causes of infection. Until the advent of anesthesia in 1846 such surgery was limited to the superficial, for example, drainage of abscesses, the redution of hernias and, sometimes, their repair. Contemporary surgery is the product of the insights and accomplishments of our historical mentors of the subsequent 150 years.