For a serial show with a convoluted chronology, is there a better invention than the DVD? Thankfully, the pre-Christmas release of “;Lost's”; Season 5 DVD set allows plenty of time to catch up on every unanswered detail before the sixth and final season begins on Feb. 2.

In addition to the delight of watching all 17 episodes in order, without a single commercial (or weeklong) interruption, the bonus features on the five-disc set are definitely the highlight. And once again, the production team doesn't disappoint.

» “;Making up for Lost time”;: Executive producers/writers Carlton Cuse and Damon Lindelof pose a series of questions, including, “;Can you change the future?”; and “;How big an impact did our characters have on events? Did they cause the incident or prevent the incident?”; The answers, of course, are coming in Season 6.

This segment also explores the logistical challenges associated with constant time travel. At one moment Dharmaville is pristine and fresh in the 1970s. In another scene it's abandoned and destroyed.

Imagine the physical labor associated with transforming Camp Erdman to this extent! Not to mention creating decades-younger versions of each character. For instance, two additional actors were hired to play Charles Widmore. Other people just needed help in the makeup trailer. For Michael Emerson, “;it's all about the hair,”; he says. “;And I try to smile less so fewer wrinkles show, and I try to put a bounce in my step.”;

Keeping every detail in the time line straight falls on the shoulders of Greggory Nations, called “;the grand pooh-bah of continuity.”; It's a big job for a man with a big notebook.

» “;Lost on location”;: One of the most informative and entertaining sections is full of short segments that explain in detail how the crew — many of whom are local and get some nice air time, particularly special-effects coordinator Archie Ahuna — make everything work. Remember the barrage of flaming arrows hurling through the sky to the beach and into people's chests and backs? You'll hear from the actors about running through this wild scene, and see how the effects crew rigged lines so that arrows ended up in the appropriate destination instead of someone's eye, for instance. You'll even watch flames engulf a stuntman.

And how about the raging storm through which six cast members paddled an outrigger canoe? Assembled in the Waipio pool complex at night, with a black tarp on the bottom of the pool and huge fans and water hoses and crew members making waves with boogie boards, it's a fascinating glimpse into the amount of time and effort that goes into preparing a few seconds of action footage. A bigger bonus: Mainland viewers get a quick lesson about outrigger canoes.

» “;An Epic Day with Richard Alpert”;: Actor Nestor Carbonell, who plays the ageless Richard Alpert, leads us through a typical day on the set, beginning with makeup and hair through scenes and location changes. It's a reminder that behind all the supposed glamour, actors really do work hard.

» “;Mysteries of the Universe”;: A fascinating blast from the past. Or is it? Presented as a long-lost (and appropriately aged) television show from the 1980s called “;Mysteries of the Universe,”; this particular investigation focused on “;The Dharma Initiative.”;

The overly dramatic Cold War-era show is highly amusing and fraught with details ranging from the Dharma Initiative logo and jumpsuits, to recruits enduring strenuous interviews and psychological testing under a cloak of secrecy before “;disappearing.”; This clandestine cult also gathered electronics, ammunition, animal care supplies and psychotropic drugs. There was even a mother/son team with the names of Eloise Hawking and Daniel Faraday. And the mode of transportation? Submarines! Which makes sense, because the Dharma colony was thought to be located on a remote tropical island near Tonga.

In clever narrative details, the show suggests that the Dharma symbol's octagonal lines — “;oriental in nature”; — are perhaps related to ... Communist China! Viewers are advised to “;be vigilant and aware of anything that may appear to be suspicious.”;

This five-episode series is available on abc.com as well.

» “;Building 23 and Beyond”;: Emerson, who recently won an Emmy for his portrayal of Benjamin Linus, shares a glimpse of the parts of “;Lost”; that are completed outside of Hawaii. The writing and editing are done in Building 23 on Burbank's ABC/Disney lot, and Emerson does a fine job strolling through the offices of writers, producers and editors (the number of people it takes to run a show of this magnitude is staggering) and chatting with them.

Emerson exhibits his usual charm when looking for himself on the graphic “;Lost”; poster in the hallway and expresses gratitude that Ben would have a place in the Season 5 finale (”;I just like to be part of it!”;).

Later, when Lindelof and Cuse ask whether he met the entire team, Emerson jokes, “;Everyone was really nice and nobody fainted and nobody cried.”;

» “;Bloopers and Deleted Scenes”;: It's always fun, even comforting, to see actors behaving like average human beings, making mistakes and laughing at themselves on the job. But the deleted scenes are a mixed bag. In some cases it's obvious why these exchanges were cut from the crisp pacing of the show. At other times, however, it's easy to sympathize with actors who turned in excellent work that ended up on the cutting room floor, so to speak. They must be grateful for life after editing on DVD.

Though the last disc contains most of the bonus features, others provide the opportunity to view a few episodes with commentary — including explanations about what happens later — from writers and producers. Listening to the bright, witty Cuse and Lindelof, the creative forces behind nearly every nuance of the show, is never dull.