From the contents: The kind and personal influence of Per-Olov Lowdin (J. Karle). - P.-O. Lowdin and the quantum mechanics of molecules (R.G. Woolley, B.T. Sutcliffe). - Symmetry breaking in the independent particle model (J.L. Stuber, J. Paldus). - The Hueckel-Hubbard Hamiltonian and its Gel'fand basis F.A. Matsen). - Different orbitals for different spins, Lowdin's idea (R. Pauncz). - The Pauli exclusive principle, spin-statistics connection, and permutation symmetry of many-particle wave functions (I.G. Kaplan). - The length and breadth of Lowdin-orthogonalizations (V. Srivastava). -...