This series is comprised of the bulk of the papers of Robert Maillart. Of note are the papers and drawings for projects as well as calculations and articles. The majority of materials are duplicates (photocopies rather than originals) from materials found in archives in Switzerland and, where possible, the location is included in the title (this pertains to folders with project numbers).

This series consists of the correspondence of Robert Maillart, primarily including letters exchanged between him and Marie-Claire as well as copies of his private letters.

This series comprises the bulk of photographs related to Robert Maillart, including bridges, construction photos, and family photos, as well as other subjects. While the majority of photographs are contained in this series, some miscellaneous photographs are scattered in Series 1 or 2 if related to a specific subject or item in those series.