Variations in concentrations of lithophile elements in samples of Apollo 15 soil can be explained in terms of only four chemical components. Three components are represented by extrusive rock types found at the Apollo 15 site: mare basalt, KREEP basalt, and the pyroclastic green glass associated with breccia 15426. The fourth component, the highlands component, can be represented by soil drom the Apennine Front, particularly the soil obtained from the 55--57 cm depth interval of station 2 core 15007/8. Among samples of Apennine Front soil, this one appears to be the least contaminated by mare materials and may be our most typical sample of the Apennine Front highlands. Althouth soil from the Apennine Front is itself a complex mixture of many types of highlands rocks, it behaves as a single component with respect to mixing with the other three (rock type) components. The various subcomponents of the Apennine Front soil (e.g., melt rock and anorthositic norite) that have been used in some mixing models are not required as discrete components in order to explain the compositional variation among samples of Apollo 15 soil. Most of this compositional variation results from mare-highlands mixing, i.e., Apennine Front soil with mare basalt. KREEP basalt, which probably derives from local (possibly unexposed) sources, is also a variable component of the soil and is most prevalent in the soil from stations LM, 6, and 9. ¿ American Geophysical Union 1987