The Metamorphosis

Gregor Samsa wakes up one ordinary morning and finds he has become a monstrous insect. He is still late for work. His family still needs the money he earns. And somehow, that is the least strange part of the story. Kafka's nightmare unfolds with the flat, patient logic of a man filling out a timesheet, which is exactly what makes it so unbearable - and so impossible to forget. Beneath the horror lies a merciless portrait of a family, and a self, worn down until only usefulness remains.
Few short novels have burrowed as deep into the twentieth-century imagination as this one. Read it in an evening. Think about it for years.