While it may be a fool’s errand to frame Leonard Cohen’s life and times through the prism of just one song, directors Dan Geller and Dayna Goldfine make a decent fist of it here. Their film shows how Hallelujah – blending gospel music with the charged speech of the synagogue – was worked on for years, then languished unnoticed before it was salvaged by John Cale, Jeff Buckley and the Shrek soundtrack. Today it’s a staple; it’s outlived its creator. And if this thorough, respectful documentary largely leaves its subject’s mystery intact, that’s probably for the best and what the singer would have wanted. Even Cohen, like the king in the song, was baffled by Hallelujah. He didn’t want to explain it and decided he probably couldn’t if he tried. He said: “If I knew where songs came from, I would go there more often.”