Luis Masperi, a long-time associate of ICTP and director of the Centro Latinoamericano de Física (CLAF), died on 2 December in Bariloche, Argentina, after a brief illness. Masperi, who was born in Spoleto, Italy, and raised in Argentina, was an internationally renowned theoretical physicist with broad-ranging research interests in particle physics, astrophysics and topology. He was also widely recognised for his dedication to world peace, having served as a member of the Pugwash council from 1999 to 2002. In addition, he shared the 1992 American Physical Society Forum Award with four other Argentinean and Brazilian physicists for their efforts in persuading Argentina and Brazil to abandon their respective nuclear weapons programme. Masperi first visited ICTP in 1966 as a young student and retained close ties with the Centre for nearly 40 years. Since 1999, Masperi had served as director of CLAF where, working in concert with the ICTP Office of External Activities (OEA), he helped to strengthen physics research and training throughout Central and South America.