Correspondence, progress reports, architectural drawings, specifications, and financial records relating to construction, maintenance, and site development of Seattle Center facilities. The bulk of the records are for the Civic Auditorium, Coliseum, and parking facilities. Most of the records date from the World's Fair and immediate post-fair development.

Correspondence, reports, newspaper clippings, and photographs collected by Massart while serving on City Council (1950-1967). Includes materials relating to Metro, Seattle Center, Century 21 Exposition, Pacific Science Center Foundation, and the Port of Seattle. Other subjects include transportation, city finances, housing, alcoholism, sports stadium, human rights, and urban renewal.