  I review the constraints placed on relativistic pulsar winds by comparing
optical and X-ray images of the inner Crab Nebula on the one hand with
two-dimensional MHD simulations on the other. The various proposals in the
literature for achieving the low magnetisation required at the inner edge of
the Nebula, are then discussed, emphasising that of dissipation in the
striped-wind picture. The possibility of direct observation of the wind is
examined. Based on the predicted orientation of the polarisation vector, I
outline a new argument suggesting that the off-pulse component of the optical
emission of the Crab pulsar originates in the wind.
