He worked in lots of genres throughout the 60s - THE FUGITIVE KIND, THE PAWNBROKER, THE HILL, FAIL-SAFE, THE GROUP, THE DEADLY AFFAIR, THE SEAGULL, BYE BYE BRAVERMAN, then there was the failure of the cod-Antonioni THE APPOINTMENT which would have emptied cinemas if it ever played in them - but Lumet certainly hit some peaks in the '70s with MURDER ON THE ORIENT EXPRESS and those great New York movies like DOG DAY AFTERNOON and SERPICO, and of course NETWORK, followed by THE VERDICT and PRINCE OF THE CITY. Another theatrical one was his film of the hit play EQUUS in '77. THE WIZ though seems to have been a misfire - I had no interest in seeing it or a lot of his later films.
Always terrific with actors and staging - the murder in THE DEADLY AFFAIR for instance - it is a terrific legacy of solid middle-brow, thought-provoking enterainment with some great performances [Signoret, Finch, Dunaway, Holden, Brando, Magnani, Steiger, Mason, Pacino etc], (I trust that does not sound too patronising).
Here are a few I cherish: STAGE STRUCK from '58 with a nice role for Joan Greenwood; the film of Arthur Miller's A VIEW FROM THE BRIDGE with Raf Vallone and Jean Sorel, the 1959 drama THAT KIND OF WOMAN, not seen until a year or two ago - where kept woman Loren has to choose between soldier Tab Hunter or wealthy George Sanders - only flaw for me was it said it was 1944 but what we see on screen in pure 1959; and the ensemble in LONG DAY'S JOURNEY INTO NIGHT in 1962 where the 4 cast members won the Venice Film Festival acting prize, providing perfect late roles for Katharine Hepburn and Ralph Richardson.