Like George Lucas’s “Star Wars” compendium and Peter Jackson’s Tolkien adaptations, James Cameron’s expanding “Avatar” series will eventually have a pre-historical section – the myth before the myth. News that Cameron is to film “Avatar 2” and “Avatar 3” back to back has been followed by his admission that there will be a prequel.

"I have an idea for a fourth," Cameron told MTV in a recent interview. "I haven't really put pen to paper on it, but basically it goes back to the early expeditions of Pandora, and kind of what went wrong with the humans and the Na'vi and what that was like to be an explorer and living in that world.”

"Because when we drop in, even in the first film in 'Avatar 1' [2009], as it will be known in the future, we're dropping into a process that's 35 years in to a whole colonization," Cameron added. "That will complete an arc and if that leads into more, we'll start, not imitating 'Star Wars,' but it's a logical thing to do because we'll have completed the thematic arc by the end of three. The only thing left to do is go back to see what it was like on those first expeditions and create some new characters that then become legacy characters in later films. It's a plan."

Unless Cameron’s original eco-sci-fi adventure had flopped badly (instead of making $2.7 billion worldwide to become the most successful film of all time), it was never going to be a one-film deal. Over two years ago Cameron told Entertainment Weekly: “I’ve had a storyline in mind from the start – there are even scenes in ‘Avatar’ that I kept in because they lead to the sequel. It just makes sense to think of it a two or three film arc, in terms of the business plan.

“The CG plants and trees and creatures and the musculo-skeletal rigging of the main characters – that all takes an enormous amount of time to create. It’d be a waste not to use it again.”

Fast-forward to now. "We've spent two years refining the whole pipeline," he said to MTV. "It was a hideously complex process to make that film and a lot has been said about that, but we don't want it to be done in the same prototypical way as the first one, we want it to be a much smoother workflow just for creativity reasons." He is still writing the scripts for parts two and three “as one big thing.”

 "You know, Peter Jackson had it easy, he already had [Tolkien’s] books," Cameron joked. "Now if I had a time machine I could go forward and watch the movies and then come back, but I don't!"

Setting aside the mercenary aspect of making six “Star Wars” films, six (instead of the requisite four) in “The Lord of the Rings”/”The Hobbit” franchise, seven “Aliens” and three “Matrixes,” and four –  let’s not rule out the possibility of more – “Avatars,” there’s something reassuring about the ongoing desire among filmmakers to spin out legends for all they’re worth, as if they were ancient bards.  That, after all, is what the creators of the Norse Sagas, the Nibelungenlied, the Mahabharata, the Mabinogion, and Le Morte d’Arthur did, among others.

One could only guess, though, what Joseph Campbell would have made of Cameron’s 10-foot, blue-skinned humanoids.

"Avatar 2" is expected to be released in 2015.