The 1999 Nobel Laureates in physics and chemistry, which were announced last month, are no strangers to the ICTP. Dutch-born Martinus J.G. Veltman, the co-recipient of the Nobel Prize in physics, was awarded the ICTP Dirac Medal in 1996. Gerardus 't Hooft, a one-time student of Veltman who shared the prize with his mentor, took part in the ICTP Symposium on Perspectives in Particle Physics in 1986 and lectured at the Spring School and Workshop on String Theory, Gauge Theory and Quantum Gravity in 1993. Veltman, professor emeritus at the University of Michigan (USA) and 't Hooft, professor at the University of Utrecht (The Netherlands), were honoured for their discovery of a mathematical tool that has advanced our understanding of theoretical particle physics. Egyptian-born Ahmed H. Zewail, winner of the 1999 Nobel Prize in chemistry, lectured at the ICTP College on Lasers, Atomic and Molecular Physics in 1985. He is a fellow of the Third World Academy of Sciences (TWAS). Founded by Abdus Salam in 1983, the TWAS secretariat is headquartered in the Fermi Building on the ICTP campus. Zewail, who was honoured for his development of a laser technique capable of detecting the behaviour of atoms during a chemical reaction, is a professor at California Institute of Technology (USA). He is the first Arab and second Muslim scientist (Abdus Salam was the first) to win the Nobel Prize.