  We use Chandra, HST and VLA observations of M87 to investigate the physics of
X-ray emission from AGN jets. We find that X-ray hotspots in the M87 jet occur
primarily in regions with hard optical-to-X-ray spectra and lower than average
polarization. Particle injection appears to be required both continuously in
the jet sheath as well as locally at X-ray hotspots.
