Anany Levitin, Introduction to the Design & Analysis of Algorithms, Addison-Wesley, 2003.
ISBN 0-201-74395-7.
This is the book used in CS365 for the Fall 2004 semester. It should be available at the Yale Bookstore. You may also be able to obtain a copy from many Internet booksellers. These may list the October 2002 publication date instead of the 2003 copyright date, but it's the same book.
Using the book:
Levitin's book is not intended to be an encyclopedia of algorithms. See the CS365/ReservedBooks list for other useful references, or follow the references in the bibliography. There are also various AlgorithmsWebPages.
Don't overlook the Hints to Exercises section at the back.