I have always thought the most underrated person in history was Judas because without his betrayal of Jesus there would have been no crucifixtion, no resurrection, no Christian religion, and all that followed. Even as a kid I used to wonder if Jesus hadn’t asked Judas to betray him in order that he might fulfill all the prophecies and acheive his purpose in life. I was pleased to see the book published a year or so ago which argued the same thing.
For this same reason I never understood why people were always so pissed at the Jews. Hey, if we hadn’t killed Jesus, nobody would ever have been saved! We did you all a fucking favor! You should be worshipping us!
Howard Florey is an Australian pharmacologist who took the laboratory curiosity penicillin and made it a practical drug that saved something like 80 million lives so far. He was made a baron and shared a Nobel prize, so maybe not so underrated. But still, the person in the street would likely give the credit to Alexander Fleming, not Florey.
Well, except there’s no particular reason to think that Christianity has done anything good for the world. For the most part, the world’s become a better place for every new injunction that’s been ignored (pre-marital sex, homosexuality, charging interest, parental worship, husband worship, selflessness, etc.). I think the only ones that remain that anyone would agree with are No Murder and No Thievery, which are hardly specific to Jesus.
The average colonist was revolting with or without Thomas Paine. They rarely bathed, and their dental hygiene was lax, to say the least. 
When dealing with explosives and other volitiles, I always like to add the caveat, “and who survived”, to the, “inventor of”, portion.
In some cases, the first inventor and evidence ceased to exist. :)
Oliver Heaviside. The areas of electronic communication & mathematics were never the same after him.
Harold Black. Inventor of negative feedback in electronics. This changed everything.
If Sarah Palin becomes president, it she will become the new title holder of most underrated. Until that day, she is rated correctly.
Everyone remembers Leonidas and Thermopylae, but Themisocles pretty much single-handledly put paid to the Persian invasion. Without him, the Athenians wouldn’t have had a strong navy. Without him, they wouldn’t have won at Salamis. Without the defeat at Salamis, the Persians could continue to supply their army by sea, Athens (and then the rest of Greece) falls permanently under Persian control and western civilisation, government and philosophy are completely rewritten.
The unknown person who, long ago, invented religion. That individual has caused more grief and misery to humanity than anyone else.
I also thought of Norman Borlaug when I saw the thread title. Very possibly the greatest human being living today.
I don’t know about the whole of history, but for the 20[sup]th[/sup] Century, I’d suggest Gregory Pincus, the father of the contraceptive pill.
You forgot the guy who invented the wheel!
“The guy who invented the wheel, he was an idiot. Now, the guy who invented the other three, he was a genius!” – Sid Caesar
It wasn’t a guy. It was some chick named Hapathumpa that invented the wheel, learned how to make fire, and domesticated horses. She was trying to invent something like a Harley Davidson but sadly she failed so she doesn’t deserve any credit for it.
This is perhaps the most intellectually vacant post I’ve read in a long,long time, which is really saying something.
I doubt there’s one single person: religion sprung up independently around the world.
I respectfully submit that being nominated here automatically disqualifies a person as most underrated person in history. Surely there are people whose tremendous contribution was not appreciated by anyone (including, for some, themselves).
I also thought of him immediately. There’s clearly some sort of meme of “Norman Borlaug is the most underrated person in history” going round (I believe I’ve seen precisely this statement on both The West Wing and Penn & Teller’s Bullshit!) which should therefore disqualify him.
Westerners seem to enjoy throwing out Jesus like he invented morality, which simply isn’t true. Human morality was largely consistent before and after Jesus, all through the world. The way one person treated another person wasn’t significantly different from Europe in Buddhist/Confucianist China for all the time from 1AD to 1800AD, and just the same in Africa or the Americas.
The influence of Christianity on history is pretty much limited to the Crusades, and the often forced conversions of people to the religion. Since neither of these is viewed as a positive thing to have done, in modern day, you can’t really say that the originator should rank highly.
This is the site for fighting ignorance. Anyone of another religion than Christianity would say that their religion is the one which produced the best, most moral people. But looking at it from a historical standpoint, there really doesn’t seem to be a large difference from one to the other. Ultimately, every tribe of people on every island is pretty nearly the same and that makes it rather hard to argue that any one religious figure is all that powerful an influence for good. Judas isn’t even that.