Claudio Pellegrini was born in Rome and studied physics at the “Universitá La Sapienza”. He received the Laurea Summa Cum Laude in 1958. He worked initially at Frascati National Laboratory in Italy and later at Institute of Theoretical Physics in Copenhagen, Lawrence Berkeley National Laboratory, Brookhaven National Laboratory, SLAC, and CERN. In 1989 he joined the University of California, Los Angeles, where he is a Distinguished Professor Emeritus. After retiring from UCLA, he joined the SLAC National Accelerator Laboratory, as an Adjunct Professor of Photon Sciences. After an initial period working on high energy physics and general relativity his research concentrated on many body, collective and self-organization phenomena in particle beams and their applications to particle colliders for high energy physics and the generation of coherent X-ray radiation with free-electron lasers. Pellegrini’s work established the theoretical and experimental foundation of X-ray free-electron lasers, leading to their construction in the USA and worldwide, opening a new window to explore atomic and molecular science and producing breakthrough new science in chemistry, physics, materials science and biology. He is a Fellow of the American Physical Society, a Fulbright Fellow and has the honors of “Ufficiale Ordine al Merito della Repubblica Italiana”. He received the American Physical Society R.R. Robert Wilson Prize and the Free-electron Laser Prize. In 2015 he received from President Obama the Enrico Fermi Presidential Award “for pioneering research advancing understanding of relativistic electron beams and free-electron lasers, and for transformative discoveries profoundly impacting the successful development of the first hard x-ray free-electron laser, heralding a new era for science.” He is a member of the USA National Academy of Sciences.