This thesis is a collection of three separate projects ordered according to the historical development of atomic physics, covering first spectroscopy, then laser cooling, and finally the exploration of quantum dynamics of many-particle states of ultra-cold atoms in optical lattices. We begin with a description of the theory of atomic line shapes with unresolvable hyperfine structure. We apply this theory to experimentally measured spectra of the Lithium D lines and report improved determination of the absolute transition frequencies and an improved bound of the difference in 6Li-7Li nuclear charge radius. We then discuss multi-photon processes in laser cooling and report experimental implementation of multi-photon laser cooling and...