Frederick Wiseman’s first documentary (1967) is a masterpiece of muckraking in which he examines the workings and inhumanities of a state mental hospital in Massachusetts. Wiseman’s focus is on the complex relationship among liberal professionals (who come off badly), guards (who come off not so badly), inmates whose only reason for being locked up is that they are “mentally ill” (whatever that means), and inmates who’ve committed serious crimes and have to be segregated. As with most Wiseman documentaries (High School, Law and Order, Hospital, Basic Training), the emphasis is on institutions and the way they dehumanize. 84 min.