OPN and Optica mourn the loss of 1987 Optica President Robert G. Greenler, who passed away on 21 September at the age of 95. Greenler joined the University of Wisconsin–Milwaukee in 1962, where his pioneering research on the optical properties of surfaces and his leadership in creating the interdisciplinary Laboratory for Surface Studies helped establish the university’s reputation in physics. He served on the faculty for three decades before becoming Professor Emeritus.