Continuing with my Shell Scott reminiscing for a moment, I believe this was the second Scott novel I read, shortly after DEAD MAN'S WALK. I checked my copy of this book and since it came out in 1967 (after originally being published as a hardback by Trident Press in 1965), that means it was probably the summer of '67 when I started reading Richard S. Prather's books.
That means I was fourteen years old. Could there have been a better age to discover Shell Scott?
And this one's got a McGinnis cover, to boot.