  Experimental work with solar neutrinos has illuminated the properties of
neutrinos and tested models of how the sun produces its energy. Three
experiments continue to take data, and at least seven are in various stages of
planning or construction. In this review, the current experimental status is
summarized, and future directions explored with a focus on the effects of a
non-zero theta-13 and the interesting possibility of directly testing the
luminosity constraint. Such a confrontation at the few-percent level would
provide a prediction of the solar irradiance tens of thousands of years in the
future for comparison with the present-day irradiance. A model-independent
analysis of existing low-energy data shows good agreement between the neutrino
and electromagnetic luminosities at the +/- 20 % level.
