52 was one of the most ambitious comics projects in recent history. It was a series released weekly, with four writers, about a dozen artists, six intertwined story lines, and no definitive ending when the project began. What is really surprising is just how good a book it turned out to be.
The writing staff, comprised of mad genius Grant Morrison, crime novelist Greg Rucka, and then Geoff Johns and Mark Waid, two of the most talented straight superhero writers in the business, pulled off a minor miracle with the story. The main characters were all amongst DC's must human (ok with the exception of Starfire, the alien warrior princess), which grounded the comics beautifully. The comic never strayed from telling truly relatable character studies, even when verging into some more absurd territories (i.e. Archbishop Lobo and his alien dolphin companion Fishy).
And simultaneously with these smaller sorts of stories, the creators managed to tell an epic adventure in which characters died, were reborn, and witnessed a fundamental change to the entire universe. I've read the story twice now, and I'm still not sure how exactly this was all pulled off. There are flaws in the story to be sure, but they're mostly forgivable given the conditions the story was written under, and the commentaries provided in the new trades go out of their way to point them all out, which really just adds to the fun.