When the Tolman/Bacher House was built in 1925, 345 South Michigan Avenue was a cozy home on a shady residential street located just a couple of blocks north of the burgeoning California Institute of Technology. Since that time, Caltech’s campus has grown considerably to envelope the house, which now accommodates the Keck Institute for Space Studies.

Throop University, Caltech’s earliest incarnation, was founded in 1891 by Amos Throop and located at the corner of Fair Oaks Avenue and what is now known as Green Street in Old Pasadena. After partnering with astronomer George E. Hale, Throop moved the campus to its current location in 1910, where it was bounded by California Boulevard, Wilson Avenue, San Pasqual Street, and Holliston Avenue. By the year 1920, when the name was changed to the California Institute of Technology, two buildings stood on the fledgling campus: Throop Hall (which was demolished in 1973 after it was severely damaged in an earthquake), and Gates Chemistry Laboratory. The three sections of the Norman Bridge Laboratory of Physics and the High Voltage Research Laboratory were added between 1922 and 1925, and by the end of the decade they were joined by the William G. Kerckhoff Laboratories of the Biological Sciences, the Guggenheim Aeronautical Laboratory, and the Dabney Hall of the Humanities. Aside from Throop Hall, which was the work of architects Myron Hunt and Elmer Grey, the campus Master Plan was designed and carried out by Bertram Grosvenor Goodhue, a renowned New York architect, and, after his unexpected death in 1924, his associates Mayers, Murray, and Phillip, along with Clarence S. Stein.

The early years of the 1930s saw the establishment of the Athenaeum, Caltech’s iconic faculty club, as well as the undergraduate residences known as the South Houses. Both of these projects, completed in 1930 and 1931, respectively, were designed by Gordon Kaufmann in the Mediterranean Revival style. In 1936, Richard Tolman commissioned Kaufmann to design the study he wanted to add to his residence. The Stock Market Crash of 1929 affected further development plans for Caltech, and some proposed buildings were put on hold for several years. Nevertheless, by 1940 the 30-acre plot of land was home to laboratories and offices for geology and astrophysics, as well as optical and machine shops. Bertram Goodhue’s original concept was nearly complete, save for the large, domed Memorial Building he envisioned to dominate the central courtyard. Although this imposing structure, which would have been capped with a blue-tiled dome and visible from any point on the campus, was never completed, Goodhue’s Spanish-themed original vision was largely realized by the close of the 1930s.

The first extension of Caltech’s campus north of San Pasqual Street took the form of the unassuming Plant Physiology Laboratory, which later became the Earhart Plant Research Laboratory, or “The Phytotron,” in 1949. These modest greenhouses were quickly overtaken, however, by an ambitious program of campus expansion spearheaded by Caltech’s new president, Lee DuBridge. The 1958 Pereira Luckman Plan proposed that a graduate housing complex, a new engineering building, and several new physical plant buildings all be established on newly-acquired property north of San Pasqual. This northward expansion was not undertaken lightly, President DuBridge calling it a “significant element of this new program.” In 1958, Arnold and Mabel Beckman offered to fund a new auditorium, and the site chosen--on the north-south axis at Constance Street--became a focal point for the northern portion of campus. The Tolman/Bacher House, which had recently passed from Ruth Tolman to the Bachers, nearly met its end during these planning stages, as the original plan called for Michigan Avenue to be moved 25 feet to the west to accommodate the grounds surrounding the new auditorium. When the Pasadena City Planning Commission turned down this plan, the little house remained where it was amidst the rapidly expanding campus presence.