This volume contains a representative selection of the papers presented at the 10th European Workshop on Quantum Systems in Chemistry and Physics, held at Beit al Hikma, Carthage, Tunisia, from September 1st to 7th, 2005. The workshop continued the series which initiated at San Miniato, near Pisa, Italy, in 1996. The workshop’s aim was to bring together chemists and physicists with a common interest in the quantum-mechanical many-body problem, in order to foster conceptual and methodological development for the understanding of the structure, dynamics and properties of atoms, molecules, and the solid state. This underpins many of the new emerging fields of science and technology: molecular engines, nanomaterials, responsive structural materials, synthetic bio-materials, drugs, and so on. Participants came mainly from Europe, but also from North and South America and from some North African countries. Among the themes discussed at this forum were such advanced topics as hyperspherical coordinates in the dynamical treatment of three-body systems; multicomponent many-body methods in the simultaneous description of electronic and nuclear motion; structure and dynamics of metal, non-metal, and ion-molecule complexes; shell effects in core ionization energies; high spin multiplicity electronic states, and the magnetism of molecular crystals. This volume should be of interest to theoretical chemists and chemical physicists involved in research and / or education.