High-energy ion-atom collisions are subject of intense investigation in present-day atomic physics. They give fundamental information on the collision mechanism of ions and atoms, and on their highly excited states. This book includes invited survey talks, and invited contributions, all carefully refereed. The topics covered are electron capture and loss (including ionization), double electron and resonance processes, electron correlation and post-collision interaction effects, collisions of antiparticles with atoms, and so forth.