"This volume collects material previously published in issues one through eleven of the Dark Horse comic-book series X, the Dark Horse comic book X: one shot in the head, issues nineteen and twenty of the Dark Horse comic-book series Dark Horse comics, and issues one and two of the Dark Horse comic-book series X: hero illustrated special"--Vol. 1, t.p. verso.
"This volume collects material previously published in issues twelve through twenty-five of the Dark Horse comic-book series X, and issues twenty-eight through thirty-one of the Dark Horse publication Dark Horse extra"--Vol. 2, t.p. verso.
X omnibus. ISBN 9781593079406. Published by Dark Horse in 2008. Publication and catalogue information, links to buy online and reader comments.