This has been puzzling me. Book 2 of the Kingkiller Chronicles is called the Wise Man's Fear. Why is it called this? There is no mention of any "wise man" anywhere in the book, and no mention either of a sea in storm, a night with no moon, or the anger of a gentle man. I got those 3 things from the book description at https://www.amazon.com/Wise-Mans-Fear-Kingkiller-Chronicle-ebook/dp/B00475AYJQ?ie=UTF8&ref_=asap_bc#navbar. So: why is Book 2 called the Wise Man's Fear?
The reference is to a philosopher's phrase that Kvothe is familiar with.
From The Name of the Wind, Chapter 43, The Flickering Way, after being caught with a candle in the Archives:
Before anything else could be said, Lorren stormed into the room. His normally placid expression was fierce and hard. I felt myself sweat cold and I thought of what Teccam wrote in his Theophany: There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man.
The phrase is referenced again by Count Threpe in The Wise Man's Fear, Chapter 51, titled appropriately enough All Wise Men Fear, as Kvothe is about to leave Imre for Vintas:
But he caught my sleeve as I turned. "Be careful on your way there," he said, his expression anxious. "Remember: There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man."
It's worth noting that Kvothe runs into all three of these things literally at one point or another in his story, and there are other more subtle references as well in Kvothe's storytelling (Felurian is once referred to as a "sea in storm"). Whether he is wise or not when he does, well, I'll leave that to each reader's opinion.