No other model series was produced by BMW for longer than the E24, built as the 628 CSi, 630 CS, 633 CSi, 635 CSi and M 635 CSi. The coupé, designed by Paul Bracq, proved to be timeless in terms of form and could be continuously refined technically. The performance increased by half, while the price more than doubled. Today, the elegant coupé is considered a classic, but one that is still waiting to be discovered. This report portrays a late coupé with catalytic converter, traces the history of its development and shows all models in many historical photos.