Phosphorus is a key element for life. This work reviews the role of phosphorus in life. Theories on the origin of life are confounded by a lack of reactive phosphorus, and attempts to overcome the dearth of reactive phosphorus must employ unrealistic phosphorus compounds, energetic organic compounds, or unusual physical conditions.Meteoritic schreibersite provided an abundant source of reactive phosphorus for the early Earth. Water corrodes schreibersite to form a mixed valence series of phosphorus compounds. Schreibersite corrosion was studied by a variety of techniques, including NMR, MS, XRD, and EPR. Reduced phosphorus in schreibersite corrodes through release of phosphite radicals which react with other radicals to form the phosphorus compounds observed. These radicals are also capable of phosphorylating simple organic compounds to form P-C and P-O-C linkages.The meteoritic mass flux was calculated using the mass frequency distribution of several meteorite collections. Much of the meteoritic mass that falls to the Earth is composed of metallic material which supplies abundant reactive phosphorus. Meteorites are a comparatively poorer source of carbon. Craters concentrate both reduced phosphorus and organic compounds through geomorphologic processes.Phosphorus and sulfur biochemistry are intricately linked in metabolism. The cosmochemistry of sulfur was studied in depth using changing C/O ratios, sulfide formation kinetics, and gas diffusion. The results have implications for meteorites, studies of Jupiter, and of protoplanetary disks.