Gambits Part 5: Another Marshall Gambit

This is definitely the most famous of Frank Marshall's gambits and probably currently the most theoretically important. I have found only one game between masters so far in 2006 where white dared to allow the Marshall, but at top levels anti-marshall systems haven't been yielding much of an advantage if any for white, they're just less worked out. Here is the critical diagram after black's 9.. d5

I've included pleanty of my personal views and explanations here.