Yesterday, I complained that many of the intellectual heavyweights of Western civilization are known not for being right but for being charismatic and asked for suggestions for people who are famous now for being right despite non-charismatic personalities.
My son suggests Mendel, the discoverer of genetics, who is probably the ultimate choice since he was unknown until after his death. Science would have benefited from him having a more forceful personality.
In management theory: surely Demming deserves more limelight?
In philosophy: I think that Hume has been overshadowed by those German metaphysicians who were always, unsuccessfuly, trying to outwit him. A special mention to David Stove who could never resist a joke. Bad move in dull but worthy fields.
In economics: The Keynsian economic scientists models and analyses were crucial in organising and administering the War Effort. Leontieff, who invented input-output analysis, and Jan Tinbergen, who introduced mathematical modelling, Kuznets for decising national accounts, Milton Friedman for designing the witholding income tax (Ha X 3) they alll deserve a guernsey.
In sociology: Weber can never get enough credit. Schumpeter was a polymath in the same league as the other Mettle European emigres.
In pol-sci: James Burnham.
Really, the interesting thing is how little social sciences have done to contribute to social technology. The big names in social science, apart from Keynes of course, have usually been flops when running government and business enterprises (eg Hayek). It looks like motivated and intelligent people can run teams without the help of egg-head advisors. Although egg-heads have their uses in summing things up for the on-lookers.
The big names in social ideology have been, both intellectually and socially, an unmitigaged disaster. We have had to spend almost the whole century unlearning what just ain't so.
In the hard sciences, strict standards of proof make harder for a charlatan to arise. Still, this sometimes happens as in the case of an obscurantist like the late Stephen Jay Gould being far better known among the general public than Hamilton or Trivers. But you can't keep a lie forever, so I think Gould's reputation will sorely fall (it already has) in the future.
What the human or social "sciences" sorely need is a good BS detector. Still, if I were to name good and underappreciated work in social science I would say that Paul Romer's work in growth theory is very good in explaining issues like the failure of depletion of resources to occur, yet he is far less known than other more prominent, less accomplished economists like Paul Krugman or Joseph Stiglitz.
John Bardeen, the only person to win the Nobel twice in physics, was a completely normal, friendly, bland mid-westerner who liked to play golf. No "Feynmanisms" whatsover. [Okay, he was a hard scientist, but he was a famously nice guy.]
If one holds that communism was the biggest disaster of last century, then the only guy who predicted it wouldn't work seems pretty important, Ludwig von Mises. He wasn't appreciated by the Nazis and then no one would give him a job in the United States. Given his predictions and body of work he has to be one of the most under appreciated intellectuals ever.
Claude Shannon, who came up with the idea of using binary numbers in computers in 1937, and invented digital communications in 1948 was a cheerful, whimsical soul who invented a juggling robot. A reader notes, "He built the original black box with one switch: when you turned it on, an arm came out of it and turned the switch back off. My kind of guy."