Low mass main sequence stellar interiors are strongly coupled moderately dense plasma mixtures that are well described by Monte Carlo simulations with electron screening included. Other applications include the very high density interiors of white dwarf stars, possible comparison with experimental measurements in laser-fusion pellet compression experiments, and the metallic hydrogen interior of Jupiter. The recent statistical mechanical results also allow the calculation of Stark broadening of X-ray lines from dense plasmas, and an accurate calculation of the screening enhancement of thermonuclear reaction rates.