Ok it’s 3 says, as in 3 Days of the Condor, both book and movie.
Any 24 episode.
There was a Johnny Depp movie whose title escapes me, but he was being blackmailed to kill someone in 2 hours. The movie was supposedly in real time, so two hours elapsing in screen time was the same as two hours of audience time.
Nitpick: The book was titled Six Days of the Condor.
Tick Tock by Dean Koontz takes place in less than 1 day. I think another of his books takes place in one or two days. Um… Intensity maybe?
“Go Set A Watchman” takes place over a long weekend.
Seize the Day by Saul Bellow.
Children’s book – Judith Viorst’s Alexander and the Terrible, Horrible, No Good, Very Bad Day 
Adult’s book – Christopher Isherwood’s A Single Man
The Divine Comedy, Easter weekend, 1300
Finnegans Wake.
You know, I read his book years ago, but had no recollection that it took place in just one day:
Philip Dick’s Do Androids Dream of Electric Sheep?
It’s been a while since I read it so I’m not 100% sure, but if the book version of Wonder Boys is anything like the movie, it takes place over about 48 hours (Friday afternoon to Sunday afternoon), with a short epilogue at the end several months later.
Great movie. Totally underrated.