For the rule To see the differences between the Revised, LHTR and Spring 1942 check the attached .pdf, made by Krieghund.
Map & setup changes:
UK Battleship on SZ13 replaced with a Cruiser UK Destroyer on SZ35 replaced with a Cruiser US Destroyer on SZ10 replaced with a Cruiser J Destroyer on SZ50 replaced with a Cruiser Formosa (J) and Iceland (UK) have been added to the map Western Canada now only borders SZ64 (on Revised it bordered Central US, SZs63 & 55) Central US now borders Eastern Canada and Panama instead of W. Canada and MexicoCan one of the moderators please make this a sticky topic?
A&A_1942_&_Revised_Editions_Rules_Comparison.pdf