Dead Ringers is the story of two identical twin gynaecologists and their problems with themselves, each other and the women they meet in the course of their work - and it's not a light romantic comedy. Beverley and Elliot Mantle are highly successful professionally but their personal lives are a mess. One is a gregarious, outgoing womaniser, the other a shy, bookish recluse, but, as the film makes clear, they're two sides of a very similar coin.

Matters come to a head when they examine actress Claire Niveau (Genevieve Bujold) and go on to share her as a lover (initially without her knowledge) - their fascination being with her body just as much as her mind, as she has a rare genital abnormality that the twins have never encountered before. But this relationship proves fatal, splitting the brothers apart and driving Beverly down a perilous path into drug abuse, withdrawal from the outside world and, most alarmingly, an obsession with the theory that his patients aren't good enough for his increasingly outlandish instruments.

Even people who normally don't have much time for Jeremy Irons have praised his performances to the skies - it's surprisingly easy to tell the difference between Elliot and Beverly, and impossible not to feel for both twins in their mental and emotional turmoil. When Irons won an Oscar a couple of years later, Cronenberg was one of the people he thanked in his acceptance speech, and it's easy to see why: not many actors get parts this rich, and even fewer pull them off quite so impressively.

Although shot in 4:3, this transfer has been made at Cronenberg's preferred 1.66:1 aspect ratio, and generally looks great - the blood-red background of the opening titles shows the overwhelming advantages of DVD over VHS (which has never been too good with this kind of material), while the source print appears to be in virtually perfect condition. The sound reproduces the original version's Dolby Stereo soundtrack - and, again, the transfer is more than adequate. There are 43 chapters - particularly generous given that the film is under two hours long.

Given that there's an alternative and cheaper R1 edition of the film, what extras do Criterion offer? Happily, the answer is "plenty", starting with an intelligent and engrossing commentary by David Cronenberg, Jeremy Irons, editor Ron Sanders, production designer Carol Spier and director of photography Peter Suschitzky that's well up to Criterion's usual standard (i.e. it sounds carefully pre-planned and edited, which is still pretty rare for a comentary track). As usual for this label, the commentary is indexed separately.

Then there's a section that pays tribute to a touring exhibition entitled "The Strange Objects of David Cronenberg's Desire", which includes the original designs for the opening credit sequence (made when the film was still called 'Twins' - it was retitled to avoid confusion with the Schwarzenegger/De Vito opus that came out first), "Mathematics in Metal", a collection of five sculptures made especially for the film, plus the film's notorious "Instruments for Operating on Mutant Women", presented here in the form of preliminary sketches plus the final creations. Every work presented in this section comes complete with full credits, including title, creator(s) and physical dimensions.

Fans of other Criterion DVDs (RoboCop, Brazil, Armageddon) will know that the company is second to none when it comes to presenting behind-the-scenes looks at special effects sequences - and this DVD is no exception; all the "twinning" effects that make Jeremy Irons appear to interact with himself are explored in detail, with technical explanations accompanied by original footage of the individual takes, demonstrating how the various elements were eventually fitted together. The process was much more complicated than the old-fashioned split-screen methods involving the camera being locked into position - and since Dead Ringers predated CGI effects by a few years, Cronenberg had to rely on sophisticated motion control equipment that enabled the two Ironses to walk down a corridor chatting while the camera moved with them.

Finally, there's the original theatrical trailer, a short (seven minute) production featurette incorporating interviews with Cronenberg and Irons and some on-set footage, and a printed essay by Cronenberg expert Chris Rodley (editor of Faber & Faber's Cronenberg on Cronenberg, among other things). No-one's ever going to pretend that Dead Ringers is easy viewing - but Criterion have done another excellent job of bringing out its virtues to the full.

Michael Brooke