I've been reading Nobel prize-winning Albert Camus's The Myth of Sisyphus, and it's been one of the most profound books I've ever read.
The basic thesis (or dilemma) is this: Life is absurd, in the sense that, when it comes to the *most* *fundamental* questions -- Why are we here? What are we supposed to accomplish? What is the purpose of life? -- not only does life not provide any answers; but in fact, life is *completely* *silent* on those questions.
The opening lines alone are enough to shake you to your core:
"There is but one truly serious philosophical problem and that is suicide. Judging whether life is or is not worth living amounts to answering the fundamental question of philosophy. All the rest — whether or not the world has three dimensions, whether the mind has nine or twelve categories — comes afterwards. These are games; one must first answer.”