  We present the latest results from a multi-epoch timing and spectral study of
the Transient Anomalous X-ray Pulsar XTE J1810-197. We have acquired seven
observations of this pulsar with the Newton X-ray Multi-mirror Mission
(XMM-Newton) over the course of two and a half years, to follow the spectral
evolution as the source fades from outburst. The spectrum is arguably best
characterized by a two-temperature blackbody whose luminosities are decreasing
exponentially with tau_1 = 870 days and tau_2 = 280 days, respectively. The
temperatures of these components are currently cooling at a rate of 22% per
year from a nearly constant value recorded at earlier epochs of kT_1 = 0.25 keV
and kT_2 = 0.67 keV, respectively. The new data show that the temperature T_1
and luminosity of that component have nearly returned to their historic
quiescent levels and that its pulsed fraction, which has steadily decreased
with time, is now consistent with the previous lack of detected pulsations in
quiescence. We also summarize the detections of radio emission from XTE
J1810-197, the first confirmed for any AXP. We consider possible models for the
emission geometry and mechanisms of XTE J1810-197.
