His later work prompted me to learn Order Theory, which has turned out to be useful for all sorts of things. Also quite closely related to Category Theory which I wouldn't have had much chance of grokking without first understanding Order Theory, I suspect.
I also used LaTeX heavily in the 80s so was surprised to see him pop up as a genius of distributed systems later (although that work was published much earlier it didn't get much exposure until the 90s). Like "oh that guy must be _really_ smart to excel in two quite different fields".
That's a good question. I don't think I found any useful books, although surely there are some out there. I believe I mostly read Wikipedia articles and posts on math stackexchange
That's a great reference which I hadn't seen before. Another thing to note is that it made more sense to me when I realized that (all) the states of a replicated state machine can be considered as points in a lattice. This I think was Lamport's insight. Once you make that connection then you can reason about replicated state machines in terms of lattices and posets, allowing for example proof of convergence or otherwise.
I also used LaTeX heavily in the 80s so was surprised to see him pop up as a genius of distributed systems later (although that work was published much earlier it didn't get much exposure until the 90s). Like "oh that guy must be _really_ smart to excel in two quite different fields".