Frank Gorshin as Billy Gannon

He was not credited, but he gave a great performance as the 19-year old, hot-headed Billy Gannon. I also read the book, where Gannon was presented as 18. For both the book and the film, I thought the casting of Gorshin as Gannon was perfect. The same applies to Fonda, Quinn and Widmark. Widmark was a little old to be playing Billy's brother, but it didn't bother me. The three leads were all older than their characters in the book. But they were all slender and rugged and looked good and very believable.