The core and valence level XPS spectra of Fe xO ( x ~ 0.90–0.95); Fe 2O 3 (α and γ); Fe 3O 4; and FeOOH have been studied under a variety of sample surface conditions. The oxides may be characterized by a combination of valence level differences and core-level effects (chemical shifts, multiplet splittings, and shake-up structure). Fe II and Fe III states are distinguishable, but octahedral and tetrahedral sites are not. The O 1 s BE cannot be used to distinghuish between the oxides since it has a nearly constant value. Fe 3d valence level structure spreads some 10 eV below E F, much broader than suggested by previous UPS and photoelectron-spin-polarization (ESP) measurements for Fe x O and Fe 3O 4. Fe surfaces (films, foils, (100) face) yield predominantly Fe III species when exposed to high exposures of oxygen or air, though there is evidence for some Fe II also. At low exposures the Fe II/Fe III ratio increases.