Beause I am one of those local bankers... I mean the workload is heave but not like what those two guys said in that book. My friends in BOCI tell me that usually they can fininsh their work after supper. That is though they have OT, they seldom stay up all night.
That really depends how the business of your bank goes. every banker wants to work overtime on WS, because if not, they may get axed next time. Monkey Business is good reference book, but it is just for first tier IB. For canada IBs or China IBs which are about tier-2 IBs at most, it may not apply. I know a tier-3 IBer in US. Man, he went home everyday at 6pm.
There is a book 'Monkey Business' which gives a good description of various roles and functions in an I Bank. Also FIASCO by Frank Portnoy, Liars Poker by michael Lewis and Barbarians at the Gate are all good reads. (also possible The Predators Ball).