The evolution of my career from purely academic research in experimental nuclear physics to science, followed by involvement in public affairs and administration, is described. Highlights in this trajectory are my involvement with the efforts to improve support for science activities and the protection of human rights of scientists in Brazil during the period of military government (1964-1984). The future role of nuclear energy in Brazil marked my transition toward a growing interest in energy alternatives and renewables. Finally, my activities first as the Rector of the University of Sao Paulo and then as a cabinet member in the federal government are described, as are the role I played in defusing the nuclear race between Argentina and Brazil and my participation in the Climate Conference in Rio in 1992.