Gregory Hallock Smith is an optical engineer and lens designer. He was born in Seattle, Washington in 1941, and was raised in Pasadena, California. His interest in photography and cameras goes back to when he was about 9 years old, but really took off when he received his first good camera, a Zeiss Contaflex, when he was 15. He has a B.A. in Astronomy from the University of California, Berkeley, an M.S. in Engineering from UCLA, and a Ph.D. from the Optical Sciences Center at the University of Arizona. Although his doctoral dissertation concerned image intensifiers, his subsequent professional work at several major corporations and research institutions has been primarily in optical engineering and lens design. His experience ranges over such areas as photographic and imaging techniques, telescopes and astronomical instruments, optics for military and NASA spacecraft, and optics education. As a consultant in 2000, he was invited by JPL to design all of the camera lenses for their Mars Exploration Rovers that have been taking pictures on Mars since January 2004. He has previously written a book on lens design, Practical Computer-Aided Lens Design, published in 1998.