Steven Stahler is a research astronomer at the University of California, Berkeley. He received his doctorate in physics at Berkeley in 1980. Following postdoctoral studies at Cornell University and the Harvard-Smithsonian Center for Astrophysics, and a faculty position at MIT, he returned to the West Coast to pursue diverse aspects of star formation theory, from the structure of interstellar clouds to the evolution of young stars themselves. Francesco Palla is a senior astronomer at the INAF-Osservatorio Astrofisico di Arcetri, in Florence, Italy. His collaboration with Steven Stahler beg...