An Oak Tree, Traverse, Edinburgh

Nobody does it quite like Tim Crouch. He's an experimental theatre-maker unto himself: exceptionally intelligent, quiet and deadpan, barely acting, weirdly gripping. As far as the visuals go, you'd hardly know there's a show on. You're looking at plastic chairs, one old scarred piano stool and a bit of sound equipment on a trolley. As for the performers, An Oak Tree is a two-hander but only Crouch has seen the script. His unrehearsed fellow actor or actress - who is different each night - is just politely asked to step out of the audience and do what he says. Sometimes he whispers instructions. Sometimes he hands them a page or two of dialogue. They also have earphones, relaying other directions - or so one assumes.

This is a piece about the power of suggestion, control and loss of control, and the form which the show takes teasingly reflects the story told. Crouch is playing a smalltime hypnotist who's mentally struggling after a car accident in which he killed a little girl on her way to a music lesson. The other player is the child's bereaved father who turns up at the hypnotist's show, unrecognised. He volunteers and falls so deeply under the hypnotist's spell that the latter thinks this guy is mucking him around and cruelly humiliates him. Then, when he agonisingly learns his victim's identity, he tries to heal the damage. The end is not without hope.

Some may find Crouch's aesthetic arid and the games with art and life contrived. But I would call this Pirandello for a modern audience and better. It's philosophy in action, playful and seriously thought-provoking. Emotionally, it is deliberately damped-down, but there's a slow burn. That you believe in and feel for the grieving father, while seeing the rehearsal-style workings, seems all the more amazing, touching and perhaps psychologically worrying.

To 28 August, 0131 228 1404