A skin graft is a transplants of skin. The most common way to do this is to transplant skin from one part of a person to another place on the same person. The technique was developed in World War II by surgeons who had to deal with people who had suffered severe burns.
Transplants of skin from one person to another is limited by tissue rejection caused by the immune system. As with organ transplants, tests are done to find a donor who is "compatible" with the host. Identical twins make the perfect donors for each other because they are genetically identical.