A surge of progress in both laser spectroscopy experiments and theoretical dynamics methods has facilitated new, highly detailed studies of water clusters. The geometrical structures and hydrogen-bond tunneling pathways of the water trimer, tetramer, pentamer, and hexamer systems have recently been characterized with global analysis of potential surfaces, diffusion Monte Carte calculations, and far-infrared laser vibration-rotation tunneling spectroscopy. Results from these and other studies are yielding important insights into the cooperativity effects in hydrogen bonding, aqueous solvation, and hydrogen-bond network rearrangement dynamics, which promise to enhance our understanding of solid and liquid water behavior.