Lord Jim

Narrated by an aging sea captain (Marlow, again), Lord Jim is the story of the title character, a sailor with romantic visions of bravery and heroism. Unfortunately, in real life Jim fails to live up to his ideals; when his ship runs into trouble, he decides in a moment of weakness to flee for safety and leave behind his fellow passengers. He faces an official inquest, but the threatened punishment is secondary to his shame and loss of honor, and the book details Jim's attempts to come to terms with his embarrassment and regain his reputation.

Conrad’s book is not just an impressive character study of Jim, but it effectively explores the importance of codes of honor (and how they function to hold society together), the possibility of redemption, and the situation-specific nature of bravery. As he did so effectively in Heart of Darkness (1899), the narrative structure (the story-within-the-story, as Marlow recounts what was told to him by Jim) gives the book the distant and hazy quality of a great fable. And his writing has never been better: 

It's extraordinary how we go through life with eyes half shut, with dull ears, with dormant thoughts. Perhaps it's just as well; and it may be that it is this very dullness that makes life to the incalculable majority so supportable and so welcome. Nevertheless, there can be but few of us who had never known one of these rare moments of awakening when we see, hear, understand ever so much — everything — in a flash — before we fall back again into our agreeable somnolence.

[...]

For it is my belief no man ever understands quite his own artful dodges to escape from the grim shadow of self-knowledge.

[...]

It is when we try to grapple with another man's intimate need that we perceive how incomprehensible, wavering, and misty are the beings that share with us the sight of the stars and the warmth of the sun.

This is one of Joseph Conrad's best and most complex novels.