German physicist (1906-1988) who won the Nobel Prize in Physics in 1986 for his work in electron optics, including the design of the first electron microscope. Two items: a glossy 4 x 6 head-and-shoulders photo of Ruska, signed in the lower border in black felt tip; and a TLS, one page, personal letterhead, November 4, 1987, in part: "The first electron microscope was built early 1931, the first image of a fine-meshed grid irradiated by electrons by means of magnetic electron lenses with more than one stage of magnification I obtained on 4 April 1931. The Ultramicrotome (the machine which slices material) was developed by other scientists only from 1955 on and was very important for the expansion of electron microscopy." In fine condition.