A. Experimental Methods.- I Heavy-Ion Storage Rings.- II Physics at the Electron Beam Ion Trap.- B. Fundamental Properties.- III Quantum Electrodynamics of Highly Charged Ions.- IV Electron Correlation Effects in Few-Electron Atoms.- V Relativistic Effects in Spectra of One- and Two-Electron Ions.- VI Hyperfine Structure of Highly Charged Ions.- VII Ground-State Lamb Shift in Heavy Ions.- VIII Laser Spectroscopy.- IX Lifetimes of Excited States in Highly Charged Ions.- X Beta Decay of Highly Charged Ions.- C. Collisional and Radiative Processes.- XI Relativistic Ion-Atom Collisions.- XII Electron-Impact Ionization and Recombination of Highly Charged Ions.- XIII Excitation of Atoms by Multiply Charged Ions.- XIV Projectile Ionization and Capture Reactions in Ion-Atom Collisions.- XV Charge Changing Processes in Ion-Ion Collisions.- XVI Rearrangement Reactions in Ion-Ion Interactions.- XVII Hollow Atoms.- XVIII Large Charged Clusters in Plasmas.