The Remarkable Field of Geometrical Optics*

In 1940, I was asked to design a Schmidt plate for an ir spotting scope. I reluctantly left a project on thin films and entered what I thought was a narrow field of specialization. Optical design was in an advanced stage of development; what would be left to do? This field has completely absorbed my interest ever since. I will briefly describe the changes that have taken place in this field since 1940. My account is not intended to be an all-inclusive record, but I hope it will portray some of the breadth of the field and show how open ended such an engineering field is.