Jerry Lewis's mid-to-late 1960's period is rarely singled out for praise but The Big Mouth is a film from that era that deserves a better fate. The script, penned by Lewis with regular collaborator Bill Richmond, frames the slapstick shenanigans with a cleverly-crafted plot that effectively uses miscommunication between as both a thematic hook and a setup for comedic setpieces. The tone is surprisingly dark, with a lot of psychological elements (like a literal doppelganger for Lewis) and the hero being driven out of his mind as literally no one will listen to his story. As was usually the case in the late 1960's films, Lewis tones down the wackiness inherent to his onscreen persona. He's not afraid to get silly but does so only at key points (he also does a delightful reprise of his Julius Kelp characterization from The Nutty Professor in a few key scenes). It helps that he has a fantastic supporting cast: Del Moore is hilarious as a perpetually annoyed hotel manager, Harold Stone makes a solid comedic straight-man as the mob boss trying to get Lewis and Charlie Callas is a scene-stealer as a crook who devolves into a bundle of nervous tics after a skirmish with the hero. Elsewhere, Susan Bay has a nice rapport with the leading man and her easygoing charm makes her a solid foil for Lewis's antics. As a director, Lewis maintains a solid pace despite the two-hour running time. His direction isn't as visually or conceptually inventive as his early 1960's work but he handles the narrative and gags in a confident style. In short, The Big Mouth is an underrated, surprisingly subversive piece of work that is a must for Lewis fans.