Black and white image of officials from the Six Companies of San Francisco and the Bureau of Reclamation, as well as some local individuals, signing the contract to construct Hoover Dam (note: Boulder Dam was officially renamed Hoover Dam in 1947). Dr. Elwood Mead is signing the contract. Seated next to him is Henry J. Kaiser. Also identified in the photograph (in no particular order) are W.R. Armstrong, Walker Young, R.F. Walter, and Louis Crampton.