I see that Up the Down Staircase will be coming to DVD on November 6. I recall being disappointed when I first saw this film for a very specific reason: it was not a comedy, and I had always thought of the book as basically a comedy. When I re-read it later I realized that it is basically a story about a young teacher trying to make a difference at a tough school where most of the other teachers have given up trying -- in other words, that the movie is faithful to the book.
But because the book is done in the form of letters (long letters by the heroine and short letters and notes written to her by her colleagues and students), a lot of it is comedy, with the students in particular doing schtick that would have fit in on Welcome Back Kotter. The makers of the movie were two of the most subdued, un-schticky filmmakers around, the team of Robert Mulligan (director) and Alan Pakula (producer) that had done To Kill a Mockingbird, so the tone is very muted and maybe not quite different enough from the average Blackboard Jungle type of movie.