Observationalists with instruments deployed on satellites, balloons, aircraft, and at the surface, to measure stratospheric aerosol or precursor gases, atmospheric chemists with interests in the stratospheric sulfur cycle and other precursors of importance for stratospheric aerosol, modelers with interests in modeling the stratospheric aerosol and its precursors and in the impacts of stratospheric aerosol on climate, and analysts with interests in the consistency of the measurement and model record.