Go Ahead, Make Some Good Mistakes

You can also read the amazing book.

How a Narrow Margin Kept Mathematicians Busy

For more than 350 years after it prevented a frenchman from sketching a demonstration of a theorem which includes the famous one by Pythagoras as a special case. This extremely well-researched and written book chronicles the contributions of outstanding mathematicians over that long journey until it was solved in 1994. It's not everyday that math is on the front pages of the New York Times, is it?