Alan Moore & Kevin O'Neill's third League of Extraordinary Gentlemen book, the Black Dossier, took an extra year to come out, but I'm glad to say that it was worth the wait. This book is something truly unique, being a sort of literary collage, even more so than the previous two books about a covert ops team comprised of various fantastic characters from British authors.
Of that team, only two remain for this volume (Mina Murray and Allan Quartermain). The bulk of the story takes place in a post Big Brother 1958, during which Alan and Mina are on the run from James Bond, Emma Peel, and "Bulldog" Hugo Drummond after stealing the Black Dossier (a history of the League commissioned by Harry Lime).
The rest of the book is comprised of the entries in the Dossier, largely prose pieces written in styles ranging from a Shakespeare Folio (featuring Prospero as an analogue to John Dee) to a Tijuana Bible (based on 1984 of course). There's also two different Cthlulu Mythos stories (one tied into On the Road, the other, in the book's most brilliant portion, to Jeeves and Wooster).
All of this is also filled with so many blink and you'll miss it easter eggs that it's pretty much required to read the annotations provided by the great Jess Nevins. Just for a few examples, Monsieur Zenith is wielding Stormbringer, Edmund Blackadder can be seen fighting alongside A.J. Raffles at the Somme, and the Pancake XL-4 rocket is blown up to make way for the Fireball XL-5.
The book is not perfect by any means. A few portions of it (the Lovecraftian Beatnik poetry clearly comes to mind) are almost too difficult to read. And the parts of the book don't necessarily form much of a unified whole. But those parts are largely brilliant.