The structural factors that keep this book selling are its function as a uniquely accessible philosophical 'gateway product' and a narrative engine that manufactures durable controversy.

Different from dense philosophical novels, *The Stranger* delivers profound ideas with extreme brevity and stylistic simplicity. It is a unique 'gateway' to existentialism, especially in academic settings, offering intellectual weight without the high barrier to entry of its peers.

The book's key mechanism is its two-part narrative pivot. Part One presents Meursault's detachment as neutral fact. Part Two then reframes that same detachment as a monstrous moral failure during his trial, creating an unresolved tension for the reader.

This structure manufactures durable controversy. By refusing to resolve whether Meursault is a monster or a martyr to his own truth, the book forces each generation to project its own anxieties about authenticity onto the text, ensuring it never feels dated.