The BMW E24 series was the first BMW 6 Series coupé, produced between the 1976 and 1989.The 6 Series name reappeared with the BMW E63 chassis beginning in the 2004 model year.
The E24 was a replacement for the CS and CSL coupés first produced in 1965. The CS 3.0 was almost changed by adding a few centimeters in height to make it easier for customers to get into the car. However, Bob Lutz rebelled against the decision and rough drafted an alternative version that soon became the 6 series. Production started in March 1976 with two models: the 630CS and 633CSi. Originally the bodies were manufactured by Karmann, but production was later taken in-house to BMW.
Source: Wikipedia, 2012