Cranioplasty is a surgical repair of a defect or deformity of a skull. Cranioplasty is almost as ancient as trepanation. There is evidence that Incan and Muiscan surgeons were performing cranioplasty using precious metals and gourds. Early surgical authors, such as Hippocrates and Galen, do not discuss cranioplasty, and it was not until the 16th century that cranioplasty in the form of a gold plate was mentioned by Fallopius. The first bone graft was recorded by Job Janszoon van Meekeren, who in 1668 noted that canine bone was used to repair a cranial defect in a Russian man. The next advance in cranioplasty was the experimental groundwork in bone grafting, performed in the late 19th century. The use of autografts for cranioplasty became popular in the early 20th century. The destructive nature of 20th century warfare provided an impetus to search for alternative metals and plastics to cover large cranial defects. The metallic bone substitutes have largely been replaced by modern plastics. Poly(methyl methacrylate) (PMMA) was introduced in 1940 and is currently the most common material used. Research in cranioplasty is now directed at improving the ability of the host to regenerate bone. As modern day trephiners, neurosurgeons should be cognizant of how the technique of repairing a hole in the head has evolved. 3-D techniques are often used to work out plate sizes, and research into the subject is ongoing.