  We discuss the observational properties of pulsar wind nebulae (PWNe) linking
them to the injected (at the termination shock) electron spectral energy
distribution and parameters of pulsar magnetospheres. In particular, we (1)
present spatially-resolved Chandra ACIS spectral maps of twelve PWNe and
measure the slopes of the uncooled PWN spectra just downstream of the
termination shock obtained from these maps, (2) consider the connections
between PWN morphologies and predictions of the magnetospheric emission models
and (3) discuss the limits on the maximum energies of particles in PWNe from
X-ray and gamma-ray observations.
