Two of the most influential cameras ever made were the German Contax and Swiss Leica from the 1920s and 30s. Unlike other cameras which used roll-film, these used 35mm movie film stock. They were very well made, had excellent optics, and because they made good images on small film, they were small, compact, relatively light and versatile. 30 years later people would still be making copies of those cameras.
In November of 1933, two men named Goro Yoshida and Sburo Uchida of japan created Precision Optical Research Institute. Their idea was to make cameras in Japan that followed the Leica/Contax model. Their company's cameras were called Kwanon, named after the Buddhist diety of mercy. But in 1935 they decided to go with a name that had no religious or regional connection, and came up with the phonetically identical (in Japanese) Canon. The company would officially change its name to Canon Camera Co. Inc. in 1951.
The early Canons were very close the Leicas of the time, enough that they could be sued for patent infrigement; they ended up soliciting help from another Japanese firm called Nippon Kogako, which would eventually become Nikon. Canon made bodies;Nikon designed and made the lens mount, rangefinders and optics, and would do so until 1947.
Throughout the 40s and 50s, Canon made a large number of "Leica-copy" rangefinders and slowly built their reputation and sales. In 1959, along with Nikon, they made the leap to making single-lens-reflex (SLR) cameras. Nikon's F would dominate the market, but Canon diversified by building a large number of cameras, from their SLR Canonflex to their rangefinder 7 and Canonets to their half-frame Demis. Bell & Howell, mostly known for their amateur movie cameras, became the US distributor and would co-brand themselves with Canon through the rest of the decade.
By 1970 Canon caught up again with Nikon as a maker of high-end SLRs, while continuing to manufacture quality cameras for the amateur niches; they made the highly regarded F-1 for professionals, the extremely popular AE-1 for serious amateurs, and Snappys for the point-n-shoot crowd.
Over the years, Canon managed to avoid the shoals that sunk so many of their competitors. In the 1980s they successfully made the transition to auto-focus SLRs with their EOS series, and when digital cameras finally caught on, they were able to introduce the high-end EOS digital SLRs and point-n-shoot Stylus and Powershots.
Nearly 75 years after their first Kwanon, Canon still dominates the camera market.