The initial collection, given by the Caltech Astrophysics Department, consists of six and a half linear feet of material related primarily to the 200-inch telescope project at Palomar. These papers include budget items, site and technical information, mostly from the 1930s, in addition to one box of material on the Morris Dam underwater ordnance project (World War II). In 1984, Professor Jesse Greenstein gave the Archives one linear foot of Rule's files from the time he was involved with the Caltech Synchrotron Laboratory. These papers contain reports, technical files and reprints. In 1986, four linear feet of papers were donated by Robert Brucato of the Palomar office. The majority of these papers are committee meetings, reports, proposals, blueprints and test data on various optical telescopes. Additionally, there are field notebooks, symposia papers and reprints. In 1989 Bruce Rule provided one file of biographical data to supplement the material in the collection.