Made on military contract during the 1960s and 1970s, originally for the US Air Force. Two blades, one a clip-point operated by the switch-blade and secured by the safety, the other a hooked cutting tool. Usually carried with the hooked blade opened in a pouch or pocket on the aircrewman's uniform, allowing rapid access to the hooked cutting edge to sever parachute suspension lines or harness. Nothing quite like being hung up in a tree or being dragged across the ground after a parachute jump.
The switch-blade (clip-point knife blade) was incidental to the primary function of the knife, probably as part of the survival equipment carried by each aircrewman.
These were also used by US Army parachute riggers, the specialists who prepared parachutes for use. The hooked blade was very handy for cutting parachute cord and other little tasks necessary while inspecting and re-packing hundreds of parachutes during a typical day's work.
Camillus was a major producer. I think Imperial also made the same product on military contracts, perhaps other makers participated.
Very collectible, especially if complete and in operable condition. As others noted, yours appears to be missing the hooked blade (primary purpose of the tool).