The invention of the transistor almost 50 years ago was one of the most important technical developments of this century. It has had profound impact on the way we live and the way we work. The first part of this paper covers the events that led to the discovery of the transistor effect and the invention of the point contact transistor in December of 1947. It continues with the development of the theory of the junction transistor in early 1948 and the fabrication of the first grown junction transistor in 1950. It is fair to say that this event completed the invention of the transistor and developed a fundamental understanding of how it worked. The second part of the paper describes the major hurdles that had to be overcome and the major breakthroughs that had to be made to turn an exciting invention into a far reaching technical innovation. This phase took approximately another 10 years. By that time, high performance, high reliability transistors could be manufactured in large quantity and at low cost. Importantly the foundation had been laid for the invention of the integrated circuit and the dramatic development of the microelectronics industry. The final part of the paper suggests some of the reasons why such an important technological innovation could occur in a relatively short period of time and be such an unqualified success. Finally, there are some comments on how much further this technology can go and when its rapid progress may come to an end.