Though it is often said that money cannot buy taste, Giovanni “Gianni” Agnelli was blessed with an abundance of both.

Grandson of Fiat founder Giovanni Agnelli and eventual head of the Italian automaker, Gianni—known as “L’Avvocato” thanks to his law degree, though he was never a practicing lawyer—enjoyed almost unimaginable wealth and privilege from birth.

Yet his unerring eye and boundless appreciation for the best life had to offer made him an international icon of style.

Often unconventional, and just as often trendsetting, Agnelli’s cultivated taste was apparent in all he touched…including this 1956 Chrysler 300B Coupe Speciale by Carrozzeria Boano.

Careful study of the design reveals details, most notably the trapezoidal grille, that echo the earlier limited-production Chrysler Specials built by Ghia; little surprise, as Carrozzeria Boano founder Felice Mario Boano had operated Ghia until 1954.

But as recounted in a fascinating, handwritten letter from Boano's son and accomp...