Neutrinos, the ghost-like particles of the Universe, have mass. The announcement, made early last month at the "Neutrino '98" conference in Takayama, Japan, generated headlines around the world. The finding also raised considerable excitement at the ICTP. Two staff scientists, Goran Senjanovic and Alexei Smirnov, have devoted much of their careers to the study of this elusive subatomic particle, which many physicists believe is the "matter" in dark matter. In 1978, Senjanovic proposed what has become a well-known theoretical mechanism for the oscillation or transformation of neutrinos. In 1985, Smirnov developed a model explaining why solar-created neutrinos may oscillate on their journey from the Sun to Earth. Oscillation is a tell-tale sign of mass. Experimentalists may now be on the verge of confirming Smirnov's decade-old model.