It is, unfortunately. It's a major Vertigo work that has never been collected in its entirety so no wonder it falls through the cracks. Pretty much everyone who has read even bits of it (like me) knows what a masterpiece it is, though.
I genuinely don't understand why Starman, Hitman and Sandman Mystery Theatre aren't perennial sellers for DC. They're among the best of the best that has ever come from the company.