A history of gray thoroughbreds and how the color survived. "We have now reached the wild frontier of the pre-Stud Book era, when a riot of exotic colors like palomino, dun, and buckskin were well attested, alongside our more familiar hues. Gray was on its way to becoming a 'museum' color too. But the thin gray line was preserved, thanks to the otherwise obscure Master Robert, whose gray posterity held on, one generation at a time, until bursting forth anew with The Tetrarch and his tribe. The vicissitudes of genetics, bad advice, sterility, and U-boats could not prevent it."