Hallett was an engineer for the Alamo Manufacturing Company, and designed the first Alamo Engine. While employed with the Hall Gas Engine Company he developed a heavy-duty gas engine. His last position was divisional chief engineer for the Hayes Wheel Company in Albion Michigan.
The collection relates to Hallett's career as an engineer and his work with engines. The collection includes correspondence, engineering notebooks, writings, photographs, patent materials, clippings, and publications,.
William E. Hallett Papers, 1900-1925, Archives Center, National Museum of American History