This is an empirical and historical study of the dynamics of technological innovation in antibacterial medicines, a key sector of the pharmaceutical industry. It is based on an analysis of all the innovations that were introduced over the period 1935-1987; from Prontosil, the first sulphonamide, through penicillin and the semisynthetic antibiotics, to the monobactams and the quinolones of the mid-1980s. In the historical section, we describe the influence that antibacterial medicines have had on the structure and research intensity of the innovating companies and through them, on the pharmaceutical industry and its geography. We also describe the catalytic role played by government agencies and universities. In the empirical section, the innovations are evaluated in terms of originality and market performance and are classified into four technological trajectories. Their distribution over time and among technological trajectories, companies and countries, the relation between originality and market performance of individual innovations, the interplay between social needs, market demand and technological innovation, the role of market-successful radical innovations in the launching of technological trajectories, the orientation of subsequent academic and industrial research and the establishment of corporate technology traditions, provide insights in both innovation theory and the dynamics of technological innovation.
