The Life and Times of Scrooge McDuck, by Don Rosa, is one of the most intensively continuity-laden comic book series ever, and yet it is an excellent and engaging comic book series for both fans of Uncle Scrooge and just fans of comic books, period.
The concept behind the series is that Rosa decided to give a "definitive" back story for Scrooge McDuck, based almost entirely upon little factoids that Carl Barks mentioned during his classic Uncle Scrooge tales. So, for instance, if Barks mentioned that Scrooge did ____ in 189_, then Rosa would work that into Scrooge's back story, making sure to address every single mention that Barks peppered into his comics (with a few exceptions that Rosa addressed where Barks seems to have made mistakes with his own timeline, mostly from early Scrooge appearances where Barks certainly did not put much thought into the character's background, never fathoming how popular this character, introduced just as a novelty Christmas character, would become).
Such slavish devotion to continuity would make Geoff Johns blush. In fact, Rosa is unique in the sense that his devotion is to a single creator. I cannot think of a single other comic book creator SO devoted to the prior works of another creator the way that Rosa devoted this storyline to the work of Barks.
And yet, the story not only works, it works splendidly, without a hint of outside writing. You would specifically have to know (or be told) that Rosa was writing this comic with Barks' stories in mind to even tell, because that's how fluid and logical Rosa makes the story flow.
Meanwhile, Rosa's story is not just logical, but it is engaging, with such ripe characterizations explored by Rosa's pen, making the characters (most of whom just get quick appearances) really leap from the page. And the adventures are not just entertaining, but Rosa manages to also make the stories based in historical fact, which makes them even more interesting!
This series won the Eisner Award for Best Continuing Storyline, and that is an honor this story well deserved. It just an excellent, excellent series and the trade only costs $17.