I am not going to write about the history of the internal combustion engine. There is already plenty written on the subject. For those that are interested in this early history and the beginnings of the motorized vehicle, I would do some reading on the following to get started:
De Dion-Bouton (company)
I enjoy reading about the early days and development of the internal combustion engine, the automobile, and the motorcycle. The above recommended topics will certainly open the door to an interesting time in history. In your studies, you will find that the camshaft did not play a very important role in the early engines.
Some Early Cam Profile Developers:
Pierre Louis Bertrand