WE PROPOSE A 126 KS XMM-NEWTON OBSERVATION OF THE FRONTIER FIELDS CLUSTER A370 WHICH ALONG WITH THE VERY PRECISE MASS MAP DERIVED FROM HST LENSING OBSERVATIONS AND EXISTING CHANDRA SPITZER AND SZ DATA GALAXY SPECTROSCOPY PLUS HYDRODYNAMIC SIMULATIONS WILL ALLOW US TO UNDERSTAND THE CLUSTER S MERGER HISTORY AND CONSTRAIN HOW HEAVY ELEMENTS AS WELL AS THE THERMAL ENERGY ARE DISTRIBUTED THROUGHOUT THE HOT CLUSTER GAS IN THIS MERGING CLUSTER. THESE GOALS ARE POSSIBLE TO ACHIEVE SINCE XMM-NEWTON OFFERS GOOD ANGULAR RESOLUTION LARGE COLLECTING AREA AND EXCELLENT SPECTRAL RESOLUTION AND BECAUSE A370 APPEARS TO BE A RELATIVELY SIMPLE MERGER OF TWO SIMILARLY MASSIVE SUBCLUSTERS.