You’ll eventually get around to making your own documentary, at which point you might adopt one of a couple of approaches. Either might lead to your being hailed a genius, or something nearly as good. The first involves giving an issue deep and patient consideration, coming to some conclusions, then figuring out the best way to put your particular point of view forward.

The second involves your coming across a juicy story in a forgotten book or your grandmother’s steamer trunk, then trying to tell the story as best you can and hoping that some sort of weight-conferring insight emerges. It’s a kind of fishing expedition, the docu-equivalent of designing an experiment and then figuring out what the hell it tests for.

Filmmaker Ann Marie Fleming inherited a story with extra pulp in the person of her great grandfather, a vaudevillian/impresario who called himself Long Tack Sam. Sam seems to have been an exquisite survivor, a charming shape-shifter, a talented and highly successful magician, acrobat and showman. Fleming tries to nail down the details of Sam’s early years in China, of his education as a performer and of his subsequent travels: to Austria where he met his future wife, to America where he became a star, to England where he made one of dozen accommodations to changing tastes by adding his young (and attractive) daughters to the show. Given that the bulk of the documented life is static, Fleming makes wonderful use of cartoons panels and animated photographs that build on the style of Terry Gilliam’s Python-era stuff. She also travels hither and yon to consult with Sam’s former colleagues, with his fans and with her relatives.

One great thing about a character like Sam is the way his experiences make history comprehensible. Textbook writers invariably focus on the deeds of speechy guys with moustaches, but when you look at it from Sam’s perspective, buffeted as he was by the changes in society, business, and politics, the machinations-of-the-moustached become less abstract. Sam’s like our Zelig: here he’s coping with the downturn in Vaudeville caused by movies, there’s his son standing behind Hitler, there’s Sam escaping the Chinese Revolution after he’d returned to escape conflict in Europe, there’s Sam and wife Poldi trying to find some place where neither of them will offend the national sensibilities of the local government.

So recounting the life of an adventurer like Sam makes compelling viewing if only to let us feel the weave of history’s fabric. But Fleming feels like there ought to be more, so she tries to tie things up with a couple of questions. One is "Why isn’t Sam remembered reverently by more of us?" But there’s no mystery there: you might just as unprofitably ask the same question of thousands of people who, despite their prodigious talents, failed to achieve the status of those few iconic abstractions who’ve survived our sieve-like memories.

She also asks "Why hasn’t my family remembered Sam?"–a slightly strange thing to ask at the end of a documentary fueled in part by the memories of her relatives. But, like the Caramilk secret, it’s kind of a riddle without much mystery, and you hardly need to know it to enjoy your chocolate.