A theoretical physicist by training, Paul Ginsparg created an open access system in 1991 for his research community to share its cutting edge results. Now called arXiv.org, and moved from Los Alamos National Laboratory to Cornell University, it serves as the primary daily information feed for global communities of researchers in physics, mathematics, computer science, and related fields. With hundreds of millions of full-text downloads/year by researchers and the general public, and ever-growing, its proof-of-concept also served as the prototype for many other modern open access systems for scientific research.