Timed to coincide with the theatrical release of The Bourne Ultimatum, the new Bourne Files 3-Disc Collection re-presents the first two chapters of the Jason Bourne saga, with a bonus third disc including a trio of featurettes on Bourne creator Robert Ludlum and the making of the first two films.

The first film, Doug Liman’s The Bourne Identity, is a taut, low-key thriller about a man with no past (Matt Damon) trying to come to grips with his remarkable abilities and with the unknown deadly past that keeps catching up with him.

The first thing he remembers is being fished out of the Mediterranean with a pair of bullet holes in his body and even bigger holes in his memory. Even his real name is a blank; “Jason Bourne” is only one of a string of identities on a pile of passports, all his, that he finds in a Zurich safety deposit box.

Although he tells Marie (Franka Potente), a girl he meets in Paris, that he’s “just trying to do the right thing,” he can’t be sure he’s the kind of person who does try to do the right thing. Perhaps his honorable aspirations themselves are a good sign. The Bourne Identity is essentially an extended chase movie, like The Fugitive, except that in this movie the Tommy Lee Jones figure (a malevolent Chris Cooper) is trying to kill him, not capture him. Fortunately, Jason discovers himself to be a much more dangerous quarry than Harrison Ford’s Richard Kimble.

When we catch up with Bourne again in Paul Greengrass’ The Bourne Supremacy, his past is still a blank, but he’s finally fully in command of his training and skills as a covert black-operations agent for the CIA. These days, when he kicks into high gear, it’s by design, not reflex.

In the tradition of the best sequels, The Bourne Supremacy extends the first film’s trajectory while telling a more complex, darker story.

There’s more plot and more action and, if the first film’s leavening human contact and flashes of low-key humor are virtually gone, Bourne’s humanity — and the moral and tragic dimensions of his situation — are ultimately brought into sharper focus. Picking up seamlessly from Identity director Liman, Greengrass brings the same acute sense of location and the same bracingly messy, unscripted realism to the proceedings.

The Bourne Identity shows us a hero struggling to learn who and what he was; The Bourne Supremacy shows us a hero beginning to struggle with who and what he wants to be, taking moral responsibility for his past life. In the first film, his relationship with Marie helps anchor him; in the sequel, though their relationship is a much smaller part of the story, its humanizing effect on him is perhaps even greater.

The Bourne Identity: Recurring deadly gunplay and violence; an offscreen suicide; some strong language. The Bourne Supremacy: Recurring deadly gunplay and violence; brief sensuality and offscreen nonmarital sex; some strong language. Both mature viewing.