For Zizek, clarity rules film, philosophy, By Damon Smith, Globe Correspondent

Slovenian philosopher Slavoj Zizek, the subject of Astra Taylor's restless, illuminating new docu-portrait ''Zizek!," may be the most well-known cultural theorist in the world (a not-so-glamorous category, but still). A professor at the Institute for Sociology in his hometown of Ljubljana, Zizek is known for marrying the arcane insights of French psychoanalyst Jacques Lacan with the hoary, Old Left critical paradigms of Karl Marx.