Book excerpt: Inner Space/Outer Space brings together much of the exciting work contributing to a new synthesis of modern physics. Particle physicists, concerned with the "inner space" of the atom, are making discoveries that their colleagues in astrophysics, studying outer space, can use to develop and test hypotheses about the events that occurred in the microseconds after the Big Bang and that shaped the universe as we know it today. The papers collected here, from scores of scientists, constitute the proceedings of the first major international conference on research at the interface of particle physics and astrophysics, held in May 1984. The editors have written introductions to each major section that draw out the central themes and elaborate on the primary implications of the papers that follow.