Abstract: The viability of prebiotic chemistry on a nascent planet is dependent on the inventory of volatile/organic building blocks incorporated during the planet's formation, particularly carriers of the elements C,H,N,O,P,S. This raises the questions: how did Earth come to obtain its prebiotic precursors, and how commonly do other planets also inherit the ingredients for prebiotic chemistry?  By studying the volatile chemistry at play in the evolutionary progenitors of planetary systems (protostars and protoplanetary disks), we gain valuable insight into these questions.  In this talk I will discuss recent progress in characterizing the chemistry of volatile species in planet-forming disks using ALMA, with a focus on how the changing physical environment alters the chemistry over the disk lifetime.  Additionally, I will highlight how complementary simulations of astrophysical ices allow us to probe chemical regimes that cannot be explored with millimeter observations.  Taken together, we are assembling a more complete picture of the volatile reservoirs available to forming planets, a key step in understanding their ultimate volatile compositions and potential habitability.