Few figures in the film world are as intriguing as Roman Polanski, the indisputably great artist whose tumultuous life behind the scenes has become far better known than any of his films.
That he had unlawful sex with a 13-year-old girl in 1977, that he fled a prison sentence in the US to live in Europe, that he was under house arrest in Switzerland in 2009 while a court considered a fresh demand for his extradition: this has become Polanski's central melodrama.
It was during those seven months of house arrest that the Polish director's old friend and producer, Andrew Braunsberg, persuaded him to film a discussion of his life.
Braunsberg proposed shooting a memoir ''just for ourselves and for his children, to have a record of his life where he would really tell the truth on a deep level. He loved the idea immediately.''
They talked for 15 hours altogether with a small crew of Polanski regulars; Braunsberg then asked director Laurent Bouzereau whether he could turn it into a film. Adding archival material and clips from Polanski's own films, he did.
Whether Polanski told enough of the truth, or told it at sufficient depth, is open to question; critics have objected that they skate over the rape charge. Unfairly, Bouzereau believes.
''It was never the intention to be the Oprah of Roman, so of course it was hard to be objective,'' he says.
Moreover, Braunsberg says, ''he admits that there is no excuse for what he did; he says it was wrong''.
Bouzereau's resonant account of the grisly murder in 1969 of Sharon Tate, Polanski's second wife, perhaps illuminates his subsequent fall from grace; it was a nightmare that, the film suggests, might have driven anyone mad. But it is the Jewish Polanski's unvarnished memories of his childhood in the Warsaw ghetto that are unquestionably the most affecting part of the film; his eyes still well up as he remembers his mother's overnight disappearance and the kindness of those who sheltered him.
Polanski was not deported in the end and, at 79, he is back behind the camera.
It is, after all, the film buff's Polanski - creator of his first Polish feature Knife in the Water, of the terrifying Repulsion, of Chinatown, Rosemary's Baby and The Pianist - who will be remembered and revered.
Unlike their author, the films never went wrong.
ROMAN POLANSKI: A FILM MEMOIR
GENRE Authorised biography.
CRITICAL BUZZ Polanski's riveting presence as a raconteur - in his third language - is unquestioned. Cannes reviewers, however, lamented his ''candour and emotionally raw recollections'' (Hollywood Reporter) were severely undercut by the fact his ''painfully ingratiating'' interviewer doesn't know anything about interviewing.
DIRECTOR Laurent Bouzereau.
FEATURES Roman Polanski, Andrew Braunsberg, Catherine Deneuve.
OPENS February 21.