The study of the origins and evolution of the Universe, can be investigated by observing the Universe on large scales, in particular the galaxies formed in the early Universe that are very distant from us. We can also better understand the Universe through ‘near-field cosmology,’ the detailed study of the formation and evolution of nearby galaxies, including the Milky Way in which we live. Marshall studies the first stars formed in our Milky Way to better understand how the Galaxy was formed early in the history of the Universe, leading to a better understanding of the cosmological principles governing the Universe as a whole.