I: Early Universe.- Big Bang Nucleosynthesis and the Density of Baryons in the Universe.- Observed Densities in the Universe.- Non-BBN Constraints on the Key Cosmological Parameters.- Stars and Stellar Systems at z > 5: Implications for Structure Formation and Nucleosynthesis.- Big Bang Theory and Primordial Nuclei.- II: Extragalactic Objects.- On the Measurements of D/H in QSO Absorption Systems.- A Reverse Monte-Carlo Study of H+D Lyman Alpha Absorption from QSO Spectra.- The Primordial Helium-4 Abundance from Observations of a Large Sample of Blue Compact Dwarf Galaxies.- Temperature Fluctuations, Hii Region Abundances, and Primordial Helium.- Towards an Understanding of the Systematic Uncertainties in Deriving the Primordial Helium Abundance from Hii Region Observations.- Primordial Helium and ?Y/?Z from Hii Regions and from Fine Structure in the Main Sequence Based on Hipparcos Parallaxes.- Extragalactic Abundances of Hydrogen, Deuterium, and Helium.- III: Low-Z Stars.- The Low Metallicity Tail of the Halo Metallicity Distribution Function.- Lithium Abundances in Low-Z Stars.- Lithium Abundance in Pop. II Stars.- Galactic Evolution of the Light Elements: A New Set of B Observations.- Key Questions for Low-Metallicity Stars.- IV: Galactic Disk, Galactic Evolution.- Measurements of the 12C/13C Ratio in Planetary Nebulae and Implications for Stellar Evolution.- Helium-3: Status and Prospects.- Mixing in Stars and the Evolution of the 3He Abundance.- Galactic Evolution of D and 3He.- Halo White Dwarfs and Baryonic Dark Matter.- The Chemical Evolution of the Milky Way Disk.- V: Solar Nebula.- Abundances of Deuterium and Helium-3 in the Protosolar Cloud.- Galileo Probe Measurements of D/H and 3He/4He in Jupiter's Atmosphere.- Evidence of Element Diffusion Inside the Sun and the Stars and its Consequences on the Lithium Primordial Abundance.- VI: Local Interstellar Medium.- Measurement of the Abundance of Helium-3 in the Sun and in the Local Interstellar Cloud with SWICS on Ulysses.- Deuterium Abundance in the Local ISM and Possible Spatial Variations.- Deuterium Observations in the Galaxy.- Local Interstellar Medium.- Epilogue.- Workshop Summary.- Author Index.- List of Participants.