1 Exact Quantum Chemistry by Monte Carlo Methods.- 47 Achieving Chemical Accuracy with Coupled-Cluster Theory.- 109 Magnetic Hyperfine Coupling Constants in Free Radicals.- 139 Calculation of Accurate Bond Energies, Electron Affinities, and Ionization Energies.- 173 Accurate Theoretical Studies of Small Elemental Clusters.- Electronic Spectroscopy of Diatomic Molecules.- 261 Theoretical Spectoscopy of Small Molecules: Ab Initio Investigations of Vibronic Structure, Spin-Orbit Splittings and Magnetic Hyperfine Effects in the Electronic Spectra of Triatomic Molecules.- Theoretical Studies of the Electronic Spectra of Organic Molecules.