Motorcycles antedate automobiles, and were developed almost concurrently with bicycles. In 1868 Ernest and Pierre Michaux of France experimented with a steam-powered bicycle. Steam engines were large, hot, and difficult to use, so performance was poor. However, the idea was basically sound.
By the mid-1880s, gas powered combustion engines had become available and an Englishman named Edward Butler attached one to his son's tricycle. Four months later Butler attached a larger motor to his own custom tricycle. (Tricycles at the time were not merely for children). His innovations were publicized and copied by others.
At this time, Gottlieb Daimler was hard at work in Germany on a variety of transportation projects. He viewed the motorcycle as a distraction, but perhaps a necessary one to raise a few dollars for his more important work. He refined an engine and attached it to an ordinary bicycle frame, and introduced the first proper two-wheeled motorcycle in 1886.
Commercial success didn't really come until the early 20th century, following the dramatic improvement of road surfaces in cities and the development of 'modern' bikes with the motor between the rider's legs and underneath the gas tank. The first bike of this design was introduced in 1901 by Michael and Eugene Werner.
Modern variations can be classified as cruisers, sportbikes, touring bikes or standards. Major manufacturers include Harley Davidson, BMW, Kawasaki, Honda and Suzuki. Others include Ducati, MV Augusta and Vespa.
Sources:
Art of the Motorcycle exhibit, Guggenheim Museum New York
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