Robert Benjamin Leighton (; September 10, 1919 – March 9, 1997) was a prominent American experimental physicist who spent his professional career at the California Institute of Technology (Caltech). His work over the years spanned solid state physics, cosmic ray physics, the beginnings of modern particle physics, solar physics, the planets, infrared astronomy, and millimeter- and submillimeter-wave astronomy. In the latter four fields, his pioneering work opened up entirely new areas of research that subsequently developed into vigorous scientific communities. Early life Leighton was born in Detroit, where his father made precision dies for an automobile company. After moving to Seattle the family broke up, and his father returned to Detroit. His mother moved to downtown Los Angeles, where she worked as a maid in a hotel. Leighton grew up in Los Angeles and completed his first two years of undergraduate coursework at Los Angeles City College. He was accepted to Caltech as a junior in 1939 but continued to live at home, helping support his mother and himself with a job building X-ray equipment for the Kellogg Laboratory. Education and Caltech Leighton received his BS in electrical engineering from Caltech in 1941. He then switched to physics and went on to obtain MS (1944) and PhD (1947) degrees from the institution. His doctoral dissertation explored the specific heat of face-centered cubic crystals. He joined Caltech's faculty in 1949 and served as Division Chair of Physics, Mathematics and Astronomy from 1970 to 1975. Leighton was a renowned teacher at Caltech. His Principles of Modern Physics, published in 1959, was a standard and influential textbook. Relationships Leighton and longtime Caltech colleague Richard Feynman were close personal friends. In the early 1960s, he spent more than two years reworking tape recordings of Feynman's Lectures in Physics course into The Feynman Lectures on Physics (1964-1966), which have enjoyed perennial success ever since. In addition, he co-authored, with Robbie Vogt, a set of problems to accompany the Feynman Lectures. One of Leighton's sons, Ralph, also collaborated with Feynman on several books. Scientific achievements Leighton was known as a remarkably ingenious physicist and astrophysicist during his 58 years at Caltech. He found no instrumentation problem too difficult, especially if it might open a new part of the electromagnetic spectrum to observation. If he found an inexpensive solution, he would build the apparatus in his spare time, for use by others and by himself. Leighton built,