A well established data base exists for the oxidation-reduction (redox) states of basalts on the Earth and on the Moon; the former equilibrate along the fayalite-magnetite-quartz buffer curve, and the latter crystallize in the field of metallic iron stability, below the iron wustite buffer. Preferred accumulation of volatiles and the disproportionation of water into hydrogen and oxygen in thick terrestrial lavas and in ponded stability. At the other extreme, lunar basalts exhibit the effects of sub-solidus reduction and estimates yield T=700--1000 ¿C and fO2=10-16 to solidus reduction and estimates yield T=700--1000 ¿C and fO2=10-16 to 10-23 atms. Based on a number of cosmogenic properties, models for planetary interiors, and the sequence of condensation with helicentric distance from the protosun, estimates for the redox states of inner solar system planetary basalts yield the following results: Basalts on Mercury and the Moon crystallize below the iron-wustite buffer curve; Venusian basalts are more oxidized than those on Mercury, less oxidized than those on Earth, and crystallization within the field of wustile stability of suggested; basalts on Earth are dominantly in the field of magnetite stability in close proximity to the fayalite-magnetite-quartz buffer curve; Martian basalts are estimated to crystallize in the upper regions of magnetite stability and well into the hematite field of stability expressed in terms of temperature and oxygen fugacity.