This work presents a state-of-the-art view of antimatter chemistry and physics, with emphasis on the nanoscopic interactions of positronium atoms with ordinary matter. Selected applications are also discussed. The chapters present a summary of contemporary knowledge in terms of both theory and experiment and look to the future of research in this area. Extensive bibliographies are included to make the volume a useful reference book. This volume is intended for a broad audience, ranging from specialists in positron research to the graduate students who should be able to use some of the chapters as the introduction to a research area.