Swamp Thing

 Len Wein & Berni Wrightson Swamp Thing (1972)
...or specifically the first ten issues, reprinted as Roots of the Swamp Thing in 1986. Wein held out for another three issues, but Berni Wrightson had already defected to various Warren titles. Swamp Thing, as you may know, was essentially a horror title, albeit one inhabiting the periphery of a world dominated by Batman and his caped pals, seemingly a rewrite of Marvel's marginally earlier Man-Thing, although Wein also had a hand in that one so it's probably not worth getting upset over.

Anyway, while this version of Swamp Thing predates the comic book having supposedly grown up, as with others of equivalent vintage, it's not exactly a kids' book either. The whole man transformed deal isn't quite Mary Shelley's Frankenstein - although there are thematic parallels - much less Dr. Jekyll and Mr. Hyde, drawing more directly from the horror comics which got Wertham so hot under the collar back in the fifties, and particularly from cinematic sources - the Universal version of Frankenstein and the adjective caligarian in issue two could refer to The Cabinet of Dr. Caligari as much as it represents Latin deployed for the sake of mood. It won't split your brain in two - unless you're unusually stupid - but it's thoughtful, intelligent, powerfully atmospheric, and beautifully drawn; and it works so well on its own terms that having Batman turn up in issue seven feels dramatically like a step in the wrong direction, although thankfully their meeting is brief.

Beyond such details, it's difficult to know what to say about these early issues of Swamp Thing except that it was a near perfect book and effortlessly wonderful. I'm reluctant to embrace twatty maxims about how everything used to be so much better in the old days, but sometimes it actually was.