The first "hardtop convertibles" were actually convertibles with a non-removable steel top. Chrysler was the first with the idea in 1946, building seven on the Town & Country 8 chassis. The first 1949 Chrysler folder (March, 1949) illustrated a New Yorker Newport 2-door hardop. It never got into production in 1949, although Chrysler did build one Town & Couuntry Newport hardtop. Oldsmobile (Holiday), Buick (Riviera) and Cadillac (Coupe deVille) were the first production models in 1949. They used the convertible body but were able to use a full-width rear seat as there was no need to make room for the folding top. The first 2-door hardtop not based on a convertible was the 1951 Nash Rambler. Yes, Rambler had a convertible, but it was the basis for their 2-door sedan! The Rambler convertible had stationary steel frames around the side glass. The first 4-door hardtop convertible was also a 4-door convertible with a steel top. Kaiser took the roof off their 4-door sedan, but had thin stationary frames around the door glass plus a non-removable glass pillar between the upper door frames. Kaiser simply took their 4-door convertible and put a steel top back on it! Over the years hardtops and convertibles went their separate ways, and the "convertible" got dropped from "hardtop convertible". Bill Vancouver, BC