Fiat's Giugiaro-designed 850 Spider was a strong seller, but also getting pretty old by 1968, so Bertone was commissioned to come up with a new barchetta. The following X1/9 was produced for 17 years.
It the late sixties, Fiat was experimenting with a front-wheel drive platform using the Autobianchi brand. So Bertone took the drive train of the Autobianchi Primula with Fiat's brand new engine (designed by Aurelio Lampredi, who came straight from Ferrari) from the 128, designed a sleek open-top body for it, and the Autobianchi A112 Runabout was born.
Introduced at the 1969 Turin Auto Show next to the Fiat X1/1 (128) and the Autobianchi A112, the Runabout was such a hit that Fiat decided to turn it into a production model. The X1/9 was launched in 1972, and even after Fiat got fed up with it in 1982, Bertone kept on building them until 1989. I want one badly.
Photo credit: Georg Schwalbach and Holger Baschleben