The current status of the experimental efforts by Davis to detect neutrinos from the sun is reviewed from the point of view of the theory of solar models. The essential physical input for a standard model of the sun is presented. Ten different hypothetical explanations of the discrepancy between the theoretically expected37Ar production rate and the observed production rate are discussed. None of these hypotheses are entirely satisfactory. One, the low Z model, is marginally attractive but it requires the sun to have a very unusual chemical composition. The errors in the fluxes from the standard model and the low Z model resulting from errors in the input data lead to37Ar production rates of5.6 ± 1.8and1.4 ± 0.35 × 10−36 atoms/target atom/sec, respectively.