With idiosyncratic filmmakers like Woody Allen and John Millius having already received the documentary treatment (a profile on the legendary Sam Fuller is also on the way), it was perhaps inevitable that the late, great Robert Altman would have the spotlight shined on his illustrious career at some point. Mirroring Altman’s own directorial approach, documentary maker Ron Mann isn’t interested in adhering too closely to the usual nonfiction conventions. He strives for a more subtle and probing approach to his subject matter and this is best exemplified in how he uses some of Altman’s past collaborators. Instead of offering up the customary anecdotal on-set tales, they’re asked to give their own concise interpretation as to what ‘Altmanesque’ means for them.

Learning his trade through several hundred hours of episodic TV shows, the Kansas City-born auteur and World War II veteran was finally able to bring his distinctive style of filmmaking to the mainstream with 1971’s MASH (he was fired for using his signature dialogue overlapping in a Warner Bros. sci-fi film two years earlier). He flourished in the studio system until a run of failed features cumulating in the 1980 Robert Evans-produced Popeye debacle – a textbook example of mismatched material if there ever was one. Showing a dogged determination to remain independent with his subsequent work, Altman’s rejection of Hollywood’s cookie cutter ethos (“I make gloves, they sell shoes”) is very much at the heart of this film.

Mann uses archival footage, essentially allowing the subject to narrative his own life. Any blanks are filled in by family members, and there’s the feeling that the production and its director is being somewhat guided by Altman’s widow, Kathryn Reed. But rather than steering the film into mawkish territory, her involvement offers a welcome heartfelt and personal perspective. The revealing home movies and behind the scenes production footage paints the picture of a fun and gregarious figure who, on more than one occasion, put his cinematic pursuits ahead of his own family. There’s no hint of sourness as one of his sons recalls his absences, rather a sad admission that making art can develop into an all-consuming obsession.

There’s the welcome inclusion of some of Altman’s more obscure works from his oeuvre, and even if the film slides dangerously close to hagiography on a couple of occasions (Mann can’t help but play out the famous eight minute opening tracking shot from The Player in its entirety, albeit in partially speeded up form), this is an absolute must for fans of the director, offering a compelling portrait of a singular talent and a true iconoclast. The documentary opens with Altman’s voiceover where he uses the analogy of a sandcastle being carefully constructed and then washed away to describe the fleeting beauty of crafting a film. This classy and comprehensive exploration into Altman’s world suggests that his legacy is anything but transitory.