Io is one of the most remarkable bodies in our solar system, with volcanoes driven by tidal heating and complex interactions with Jupiter's magnetosphere. Despite extensive studies from the ground and from spacecraft, fundamental questions, concerning the nature and location of internal dissipation, the composition of the dominant magma, and the interactions among the volcanoes, surface frost, atmosphere, and Jupiter's magnetic field, remain unanswered. The proposing team will conduct an extensive observational program of imaging and spectroscopy to monitor Io's volcanoes and atmosphere, making use of a wide range of telescope facilities including the Atacama Large Millimeter/Submillimeter Array (ALMA), the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), the Infrared Telescope Facility (IRTF), and the Gemini and Keck Observatories. These observations will yield (1) global maps of Io at 1-5 microns, at least once a year, to map and monitor volcanic activity; (2) determinations of the sulfur monoxide gas distribution while Io is in Jupiter's shadow; (3) observations of sulfur monoxide and sulfur dioxide gases to constrain the structure of and dynamics in Io's atmosphere; and (4) correlations of atmospheric sulfur monoxide and sulfur dioxide gases with sulfur dioxide ice and volcanic hot spots. The global infrared maps of Io, will be integrated into the USGS global Io database. The project will support the work of undergraduate and graduate students, and proposing team members will be involved in a variety of public outreach activities.