1 Dominic Monaghan, who plays Charlie, became so frustrated with "monster theories" that he had a T-shirt made with the words "I don't know" printed on it.
2 Here is a hint about the monster -- it's not a dinosaur. Lost creators JJ Abrams and Damon Lindelof indicated the mystery would be resolved at the end of the first series, but do not expect a straightforward solution.
3 Abrams is obsessed with the number 47. All his TV shows, including Alias and Felicity, are full of references to 47 and it is no coincidence there are 47 survivors (after the marshall who was taking Kate to prison dies). The other significant number in the show is 40, the number of days in the first series. It is no coincidence that it relates to the 40 days and 40 nights in the Bible.
4 Evangeline Lilly almost lost out on her role because she is Canadian. "We couldn't get her a visa so we started shooting on the first day without her," Lindelof says. "We needed her on day two and if couldn't get her, we'd have had to go with someone else."
5 One of the main cast members will be killed off by the end of the series. "We've been told for sure that one of us will die," Lilly says. "We're all on our best behaviour. I'll do whatever, but please don't kill me."
6 When the cockpit is found, the name Oceanic is seen. It is a fictitious airline but the name has been used in other shows, including JAG.
7 The Australian farmer (played by Aussie actor Nick Tate) who betrays Kate has a prosthetic arm. That detail is a tribute to one of Abrams' favourite series, The Fugitive, which featured a mysterious one-armed man.
8 The actor who plays the monster's first victim, the airline pilot, is not credited. He is played by Abrams' childhood friend Greg Grunberg, who stars as Eric Weiss in Abrams' other hit, Alias. "I didn't know I was going to get yanked out of the plane," Grunberg says. "But if you're going to have a cameo, it's a cool one."
9 Grunberg "saved" Matthew Fox's character. In the original draft, Dr Jack died in the first episode. "I remember reading it and thinking, 'No way'," Grunberg says. "This is the character everybody connects with and everybody loves. You can't have him die, so they rewrote it."
10 There is a big Australian connection to the show. The ill-fated flight leaves from Sydney and one of the main characters, the pregnant Claire (played by South Melbourne's Emile de Ravin), is an Australian -- but all the flashback scenes set in Australia were done in Hawaii.