The Case Study House program, initiated in 1945 in Los Angeles, remains one of America's most significant contributions to architecture at mid-century. The motivating force behind the program was John Entenza, a champion of modernism and editor of the avant-garde monthly magazine Arts & Architecture. Entenza envisioned the Case Study effort as a way to offer the public and the building industry models for low-cost housing in the modern idiom, foreseeing the coming building boom as inevitable in the wake of the drastic housing shortages during the depression and war years. Using the magazine as a vehicle, Entenza's goal was to enable architects to design and build low-cost modern houses for actual clients, using donated materials from industry and manufacturers, and to extensively publish and publicize their efforts.

When the American Institute of Architects, California Council (AIACC) handed out its annual citations to architects and allied professionals, in June 2001, its 25-Year Award was presented to Case Study House #21 designed by Pierre Koenig, FAIA. This honor recognizes a California project, at least 25 years old, that has "retained its central form and character, with the architectural integrity of the project intact."

Contributors to the case Study House program ranged from architects who were to attain international reputations - Richard Neutra, Charles and Ray Eames, Eero Saarinen, Craig Ellwood and Pierre Koenig - to those whose reputations remain primarily localized, such as Whitney R. Smith, Thornton Abell, and Rodney Walker. Architects who participated in the program did so at the invitation of Entenza himself, and therefore the roster of participants clearly reflects his personal predilections rather than a comprehensive overview of American, or even Californian, approaches to low-cost modern house design. During the initial years, an improvisatorial spirit dictated many of Entenza’s choices of architects and designs.

Several early projects conceived as Case Studies were never built because they lacked actual sites or clients. Those that were built often changed greatly from the architect’s original vision, owing to building material shortages or other difficulties surrounding the undertaking of construction in the immediate postwar years. A few of the early built houses were even brought into the program after being designed in order to continue some degree of momentum for the Case Study effort during breaks in its continuity. In one instance, Entenza himself served as client for a Case Study house designed by Charles Eames and Eero Saarinen, while Charles and Ray Eames themselves were the client for their own Case Study House.

Conceived as experimental modern prototypes, the 36 designs of the program epitomised the aspirations of a generation of modern architects active during the buoyant years of American's post-World War II building boom. By its end in 1966, the Case Study House program had succeeded in producing some of the period's most important works of residential architecture. Today, the Case Study houses continue to have wide relevance and influence within architectural culture, not only in Los Angeles, but also nationally and internationally. These houses, and the spirit behind them, serve as a model for architects committed to reductive, yet experimental, modes of residential design and construction.