The collection includes specification documents for approximately 170 architectural projects by Frank Lloyd Wright. Highlights include specifications for American System-Built houses (#1506), Imperial Hotel (#1509), San Marcos-in-the-Desert resort hotel (#2704), Fallingwater (#3502), Solomon R. Guggenheim Museum (#4305), H.C. Price Company tower (#5215), Lenkurt Electric Company (#5520), and Marin County Civic Center (#5746). Specification documents range from descriptions and instructions regarding the quality of work and materials to guidelines for plumbing, electricity, wood, metal,and painting work. Also included in the collection can be correspondence, contracts, structural calculations, licenses and subcontracts for design objects and furnishing.