The LII,III region of absorption has been observed for thin films of evaporated aluminum, for amorphous (anodized) Al2O3, and for crystalline (γ-alumina) Al2O3. The spectra were obtained in high resolution (0.06), using the NBS 180-MeV electron synchrotron as a background source. The LII,III absorption edges of Al are located with improved accuracy at 169.49±0.05 and 170.49±0.05. This new value for the LIII edge can be combined with recent accurate determinations of the Kα1 emission line to locate also the K absorption edge of aluminum with a significant improvement in accuracy. Structure on the high-energy side of the LII,III edges is compatible with other recent observations. The L absorption edge of Al in Al2O3 is not split in high resolution, and is located at 162.11±0.15 for the amorphous form and 160.15±0.15 for the γ-alumina. Both forms show considerable structure on the high-energy side of the edge. That observed for the amorphous form is in agreement with other recent observations, while the absorption structure in γ-alumina (with maxima at 78.0, 78.6, 79.5, 84, and 99 eV) is reported here for the first time. © 1968 The American Physical Society.