Coward Fiction
One of my favourite genres of books is about a character discovering – in the moment of truth – that he's a coward. My personal pantheon is The Caine Mutiny and Beware of Pity, though I think Lord Jim is supposed to be the classic. (It's probably not a coincidence that these books are from 1951, 1939 and 1900 respectively).
People talk a lot about the benefit of Reading Fiction in learning to empathise with the experiences of others. A special element of reading Coward Fiction is that you're learning to empathise with an experience that will be yours. There's a high chance that sometime in your life you will be faced very suddenly with a demand for bravery, and (just statistically!) it's incredibly unlikely that you'll live up to it. Until it happens, it'll be hard to believe, or understand. I don't think reading about it actually makes you understand it, but at least maybe gives you a glimpse of it.