After a trilogy of action-packed espionage thrillers adapted from the best-selling novels by Robert Ludlum — "The Bourne Identity" (2002), "The Bourne Supremacy" (2004) and "The Bourne Ultimatum" (2007) — Matt Damon had had his fill of playing the intrepid secret agent Jason Bourne. But just when you thought you'd seen the last of the series, there is "The Bourne Legacy," featuring Jeremy Renner as an alter ego of sorts named Aaron Cross, who finds himself in equally precarious situations.

Based on an original screenplay by director Tony Gilroy — who collaborated on all three of the earlier "Bourne" scripts and who received an Oscar nomination for directing 2007's "Michael Clayton" — the new sequel co-stars Edward Norton as a bureaucratic heavy and Rachel Weisz as an imperiled scientist (with cameos by the likes of Joan Allen, David Strathairn and Albert Finney, reprising their roles from the earlier installments). The movie opens in theaters on Aug. 10.

Gilroy, 56, spoke about the new movie during a recent telephone interview from Toronto.

Q: You worked on the screenplays for all three of the earlier "Bourne" movies. As a director, though, did you have any reservations about jumping into a franchise that was started by others?

A: My initial anxiety was just the normal anxieties you always have as a director. It wasn't so much about trying to measure up to anyone else, but it was such a huge undertaking, I did find myself wondering what I'd gotten myself into. This was never anything I'd really thought about or ever anticipated doing. Plus, it all came about in such a random way, really late in the pre-production process. The only ground rule was that there would be no more Matt Damon, so it actually started as a game for me, trying to think of a way to move the story forward without him. Once the character of Aaron Cross came into view, though, things got a lot more interesting, so that by the time I started thinking about directing it, it was a rather fully formed story, and everything else sort of fell into place.

Q: Was the objective to replicate the style and spirit of the other "Bourne" movies, or to put your own stamp on it and make it your own?

A: My main objective was that every decision be based on authenticity, whether it was the physical side of the story or the emotional and behavioral life of the characters. That's what I always strive for, to make everything as real as they can be. The studio had expectations of making it bigger, upgrading the action, so in a way, I felt I had a legitimate right to break free from what Doug [Liman] and Paul [Greengrass] had done in the earlier films, to expand the landscape of the story and to shake up the visual vocabulary a bit.

Q: At what point does a franchise like this fulfill its purpose, if not when the leading actor decides to bow out? It almost seems like cashing in on the brand name, when you might've excised any and all references to the Bourne character and just told the story of Aaron Cross.

A: It was a tricky thing to maneuver, but that was part of the fun for me. I suppose we could've done it as the Aaron Cross story, but then we would've missed out on the cool and exciting concept of interlacing the two stories. That's a kind of approach you don't often get the chance to take. I was intrigued by the idea of doing a next chapter or installment in an ongoing story.

Q: Talking about the casting of Jeremy Renner?

A: We knew we had a really complicated character with a lot of different colors to play. We knew we needed not only an absolutely proper actor, but also a movie athlete who would be physically able and ambitious enough to go through what we needed him to do.

Q: And Rachel Weisz?

A: We didn't want to simply put a pair of glasses on some starlet and expect audiences to believe her as a scientist. We had a very short list of candidates who were both age- and intelligence-appropriate. Rachel was someone who could economically portray the chaos of the character, without the luxury of a lot of time to spend telling her back story.

Q: And Edward Norton?

A: Well, he was someone I had to chase for a few months. He didn't want to do it. He wouldn't be playing the lead. He'd be playing about the closest thing there was to a villain in the story. He had a lot of different and totally legitimate issues, but I really pursued him. Once we met, we really got along, and he brought a lot of extra complexity to the character.