Artists vary between volumes.
Vol. 1 originally published 1983-1985 by First Comics in Starslayer issues #10-17 and Grimjack issues #1-13.
Vol. 2 originally published by First Comics as Grimjack issues #14-30.
GrimJack omnibus by John Ostrander. ISBN 9781613770009. Published by IDW Pub. in 2010. Publication and catalogue information, links to buy online and reader comments.