The Sun's magnetism powers the solar wind, the gradual and impulsive X-ray and extreme ultraviolet emissions, coronal mass ejections, and energetic particle events. Interaction of these diverse phenomena with the Earth's magnetic field and atmosphere cause a variety of conditions that we know collectively as space weather. With the rapid development of the technological infrastructure upon which modern society depends comes a growing appreciation of the hazards presented by space weather, be it in moderate conditions or during extreme events: disturbances in the electric power grid, problems with radio communication, and deviations of navigation systems are some of the many manifestations of space storms. In this talk, I outline some of the physical processes involved from Sun to Earth, arguing that in order to better shield society against the impacts of space weather, we need to better understand the processes involved. COSPAR and the International Living With a Star program recently tasked a multi-disciplinary, international team with the development of a roadmap with the goal of demonstrably improving our observational capabilities for, scientific understanding of, and ability to forecast the various aspects of space weather; its main recommendations will conclude my presentation.