X-men: God Loves, Man Kills

No individual writer is more important to undedrstanding the rise of the X-Men as the major force in 1980s comics than Chris Claremont. He redefined the team, modernized, and even humanized, them. WHile he work with John Byrne is the best known, the original graphic novel X-Men: God Loves, Man Kills, sees him work beautifully with Brett Anderson handling the art.  X-Men: God Loves, Man Kills somewhat proved that a story that is not necessarily a part of canon, but is at least canon-adjacent, can work in the graphic novel format. Here, it's a very specific slice of time, later put in between Uncanny X-Men #s 167 and 168, that is explored, and the emotional journey of the X-Men as a whole is expanded on in a very natural way, something that would be difficult to do in a single comic issue, or to sustain over an arc. This is one of Marvel's Original Graphic Novel netries, and while not the first, it certainly was the one that made it certain that the graphic novel format would be with the company for a long time.  Why it's on the list: Marvel's graphic novels helped to define how they would fit in with the traditional super-hero mode of comic, and it did so with great material presented with precision and grace.