Donald Dilworth is president of Optical Systems Design Inc and has been intensively involved in the development and application of computer software for optical design since 1961. He has extensive experience in most areas of lens design, particularly in thermal infrared systems, and he is the author of the well-known SYNOPSYS lens design program, which is used by lens designers worldwide. As author of SYNOPSYS and developer of the popular Pseudo-Second Derivative optimization method, Dilworth has advanced the state of the art in artificial intelligence.  Dilworth was senior principal development engineer at the Honeywell Radiation Center, where he was responsible for conceptual and detailed design, tolerancing, and analysis of numerous infrared and visible-light systems, including star trackers, periscope optics and forward-looking infrared systems. He also served as director of the optical design department at Baus Optics Inc, where he developed and implemented techniques for the design of geometric and thin-film optics. Prior to joining Baus Optics, he was employed by Itek Corp as senior optical physicist. In this capacity he was responsible for designing a variety of advanced optical systems, including aerial photographic lenses used on the recently declassified Corona project, aspheric systems, multilayer dielectric coatings and a submarine periscope. At the Massachusetts Institute of Technology, where he received a BS in physics in 1961, he developed computational techniques for optical and thin-film design, which were applied to the design of the optical navigation equipment for the Apollo project.