It`s hard to see back more than 15 years to the time before Swamp Thing. Back before superheros grew up, went all philosophical and got buried under their own ludicrousness. Before Alan Moore came along the US comic was a sad tired thing. Moores`Swamp Thing was a revolutionary statement of intent, it changed everything. Not immediately, it took everyone else a while to catch up . In it`s scope , it`s depth and it`s inventiveness , Swamp Thing was hugely ambitious. It dealt with issues, big ideas, morality and frail human feelings. Very few people had even attempted to deal with this kind of thing in a monthly US superhero comic, most people would just have assumed that it was impossible.
Now I`m not saying it`s the perfect comic, it`s flawed, particularly at the end of the saga , but if you want to see where The Sandman and all the ensuing Vertigo stuff actually germinated from, then you need to read Swamp Thing, it`s the very root of it all and is still an extraordinary and wonderful comic.
I`m sad to see that only a relatively small number of the collected volumes are still available. I hope there are reprints planned.