  We present a new analysis of parton distributions of the proton. This
incorporates a wide range of new data, an improved treatment of heavy flavours
and a re-examination of prompt photon production. The new set (MRST) shows
systematic differences from previous sets of partons which can be identified
with particular features of the new data and with improvements in the analysis.
An `explanation' of the behaviour seen on the Caldwell plot is offered.
