Tonight begins the two-part, three hour long finale of this most wonderful of seasons of Lost. The ABC mind-bender show has been in top form this year, with its tantalizing ballet of bobs and weaves, feints and hints. We now know who the Oceanic Six are, but still not why they are (we will learn something about that tonight). We know a little about time travel, some new tidbits about the island's history, and a little more about who's gonna dieeee (Chahhlee.) As we slowly start to bundle up for the long, cold nuclear winter of having no Lost until next January, let's enjoy these final moments. Here is EW.com's Doc Jensen with a typically thorough and engaging episode preview and, after the jump if you're so inclined, are some sneak peeks from tonight's installment. (With a familiar face, for Battlestar Galactica fans.) The real kicker, though? We don't even get a new episode next week! Bah.