Below is a list of recommended texts (several of which will be used in the program). The book by Boas contains most of the mathematics that entering students should be familiar with, while the early chapters in Hull's book are a good introduction to the financial products that are the basis of study for the program.
Some other recommended readings. These are more to get a feel for how business works on Wall Street and not everything is centered around quants. Here are Neil_chriss' picks:
Some picks by Robert Frey: