Start with Guns, Germs, and Steel and/or Digital Minimalism ;)
It's also useful to know that Diamond does not have a degree in Geography and many geographers aren't particularly on board with his ideas.
I think of him the same way I do Malcom Gladwell, a good story teller but he does this by cherrypicking anecdotes more than by a robust assessment of reality.
Jump to 'The Power Broker' instead. Now that's an interesting read.
I've read a couple of the LBJ books which are really amazing and plan on getting to power broker eventually.
He has degrees in history and anthropology and has been a professor of geography for decades.