Foreword.

I don't know why I was attracted to prosthetics and orthotics. But I can guess at some of the reasons. About 40 years ago, as the youngest surgeon, I was assigned to the crippled children's hospital where no surgeons were interested in prosthetics and orthotics. At that time, the polio vaccine had not been invented. Many polio victims were waiting for orthopedic treatments. Some surgical treatments went well, but some did not. Braces in some cases worked very nicely. The braces did not cause pain in the children, and sometimes they helped children who could not walk to walk. So I studied prosthetics and orthotics with no obstacle.

At that time, it was very hard to …