If, as F. Scott Fitzgerald once wrote, fewer than a half-dozen people have ever held “the whole equation of pictures in their heads,” one of them must be Walter Murch, the eighty-two-year-old editorial wizard who worked on the “Godfather” films, “Apocalypse Now,” “The Conversation,” and a dozen other masterpieces. Murch’s new book, “Suddenly Something Clicked: The Languages of Film Editing and Sound Design,” may take you weeks to read, as you stop to look at the movies that Murch dissects with meticulous verve. You will, for example, want to rewatch the scene of Don Corleone’s funeral, filmed at Calvary Cemetery, in Queens, once you learn that the background traffic noise was recorded at 3 A.M. on a Highway 101 overpass in the Hollywood Hills. The sound, Murch writes, was “lonely, with something strangely spiritual about it, like shimmering violins, or, sometimes, buzzing bees.”