Correspondence, memoranda, diaries, journals, logbooks, drafts of writings and speeches, reports, notes, financial papers, biographical and genealogical material, scrapbooks, newspaper clippings, printed material, blueprints, patent specifications and descriptions, drawings, photographs, and other papers documenting the careers of Piccard family members in the fields of aeronautics, ballooning bathyscaphe exploration, chemistry, education, religion and stratoospheric exploration. Includes Ridlon family papers and Swiss legal and genealogical documents concerning the Piccard family dating from the 1470s to the late 18th century. The papers of Jean Piccard document his career as explorer, inventor, and scientist collaborating with his brother Auguste on balloon flights for stratospheric exploration and the study of cosmic rays and on other mutual scientific interests; as organic chemist and consultant with Calco Chemical Company and Hercules Powder Company; and as professor of aeronautical engineering. Includes material pertaining to the Piccards's stratospheric balloon flight of 1934 and to Jean Piccard's 1937 test flight in the aerostat Pleiades. Also includes records Piccard Kept as treasurer of the Aero-Club Suisse and transcript of interrogations which he conducted for the U. S. Army Air Forces in 1945. Papers of Jeannette Piccard pertain chiefly to her role as member and priest in the Episcopal Church; her work as aerospace consultant with the National Aeronautics and Space Administration; and her career as an educator. Donald Louis Piccard's papers include his files as editor of the National Balloon Federation newsletter nd material pertaining to his sport balloon manufacturing company, Don Piccard Balloons, Inc. Family corresondents include Auguste Piccard, Jean and Auguste Piccard's father Jules, Jeannette Piccard's father John Ridlon, and Jean and Jeannette Piccard's son Jacques, granddaughter Kathryn Ann Piccard, and several foster children. Other correspondents include Denzil A. Carty, Daniel Corrigan, Albert Einstein, Robert R. Gilruth, Suxanne R. Hiatt, Philip F. McNairy, Robert Andrews Millikan, A. W. Stevens, W. F. G. Swann, and Francis Zielinski. Includes correspondence between Jean Piccarad and the National Research Council concerning trinitrotoluene (TNT)