Overview of the complex chemistry in starless and prestellar cores

Historically depicted as 'voids' or 'obscuring bodies' in the visible night sky, starless and prestellar cores are now defined as singular 'units' of star formation. These objects are budding chemical laboratories filled with molecular gas and dust, most often probed by submillimeter and infrared facilities, that set the initial conditions important for understanding the later stages of star and planet formation (e.g., protostars, disks, and comets). In this review, I will summarize what we know about the increasing chemical complexity found in this early stage, specifically those molecules that are precursors to more biologically relevant species such as amino acids, DNA, and RNA. The growing prevalence and abundance of complex molecules in starless and prestellar cores, both in the gas-phase and ices, suggests at least some of their chemical composition is inherited to the later evolutionary stages. As we look to the future, there is much more work to do in order to expand our understanding of the evolution, spatial distribution, ice composition, etc., of starless and prestellar cores, with facilities like ALMA and JWST as well as ongoing chemical modeling efforts and laboratory studies.