This monograph describes a study of entrepreneurship in new technologically-based firms. The work is based on empirical data gathered primarily in interviews with individuals who formed such enterprises. Most of the research was conducted in one of the nation's centers of technological entrepreneurship, the San Francisco Peninsula area around Palo Alto, California. Focus is on the founding of new technologically-based firms. Such new companies are rare, and the study examines the factors that create an environment in which an entrepreneur may take the step of starting his own firm. Spin-offs from established organizations appear to function as incubators to a great extent. One of the most important factors is the development of markets and technologies on which the area's industry is based. But the individual entrepreneur, his background and characteristics, is the paramount influence. The monograph concludes with implications for established firms, implications for prospective entrepreneurs, and implications for regional economic development of factors favorable to technical entrepreneurship. (MF)