Abstract: A retractable roof system for motor cars, said system comprising: a plurality of nesting shutters interconnected for movement between a nested position and an extended position in which each shutter overlaps an adjacent shutter and the outer surfaces of said shutters altogether define a substantially horizontal essentially continuous, stepped, extended surface, a pair of fixed guide members adjacent, respectively, the lateral margins of said extended surface, and followers attached to the shutters for cooperation with guide members to position the shutters so that said extended surface generally matches a desired surface for said roof system. The system includes interchannel sealing strips which inhibit the passage of wind and rain into the motor car and also serve to reduce vibration by compressing and maintaining spacing between the several shutters.