Bernard Vonnegut I was grandfather to which author who wrote "Slaughterhouse-Five"?
Bernard Vonnegut I:  He is the namesake and grandfather of scientist Bernard Vonnegut, father of the architect Kurt Vonnegut Sr., and grandfather of author Kurt Vonnegut. Kurt Vonnegut:  He is most famous for his darkly satirical, best-selling novel "Slaughterhouse-Five" (1969).
Kurt Vonnegut