Richard Feynman is a physicist who needs next to no introduction; he was an extremely intelligent and prolific scientist who made major contributions to many fields, ranging from electrodynamics to subatomic and nuclear physics. He is also credited with being a pioneer for quantum computing.
Feynman gave a talk on simulating physics with computers at a conference in 1981. It was here that he he proposed the idea of using quantum computers to simulate quantum systems that are too hard to simulate using conventional classical digital computers. He beautifully speculated,
Can you do it with a new kind of computer — a quantum computer? Now it turns out, as far as I can tell, that you can simulate this with a quantum system, with quantum computer elements.Richard P Feynman. Simulating physics with computers, 1981. International Journal
of Theoretical Physics, 21(6/7).
These ideas were expanding upon by many prominent figures, like Yuri Manin and Paul Beniof, at a high level. Remarkably soon after, it was with individuals like David Deutsch and Peter Shor where the concept of a quantum computer was formalized, and algorithms theorized to provide a speedup over classical methods.
Fast forward to today, and we are seeing quantum hardware and physical qubits being realized. Organizations like Google, IBM, 1QBit, D-Wave, Honeywell, and more are leading the effort in brining universal quantum computers and quantum software to the world.
For more on the history of quantum computing, please see this paper.