The year 2013 marks the 80th anniversary of the discovery of the positron, i.e., the antiparticle of the electron. The positron was first predicted by Paul Dirac's theory of the electron, which is arguably the simplest possible theory consistent with both quantum mechanics and the theory of relativity. It suggests a mirror world of the one we know -- a world in which every particle has an antiparticle. This concept is truly an astonishing idea for which there was initially no experimental evidence. Yet the discovery of the positron, and subsequent discoveries of other antiparticles, indicates that we are indeed embedded in such a world. One of the towering mysteries is why we do not see antimatter all around us -- or to be more precise, why there seem to be no large domains of antimatter in the universe. The supposed perfect symmetry between matter and antimatter should have resulted in equal quantities of each being produced at the Big Bang. Perhaps there are indeed large reserves of antimatter out there that we just have not seen yet.  This symposium will discuss the most recent searches and the paths to further investigation. Or perhaps the matter/antimatter symmetry is not quite so perfect after all? Within the past two years, the most precise experimental tests have been made of this postulate. Hybrid systems -- molecules made of particles and antiparticles -- are also now in view.