The AXAF, the x-ray component of NASA's great observatories, will launch in 1999. As integration and testing of the flight system are concluding, analysis of the ground calibration data continues. This analysis verified AXAF's unique capabilities for high-resolution imaging and for high-resolution dispersive spectroscopy. However, it finds unexpectedly high residuals between the data and the model for effective area of the AXAF optics. Reconciling the physical model with the data, to an accuracy of a few percent, remains a goal of the analysis and interpretation of the calibration data.