The Putnam Mathematics Competition

The William Lowell Putnam Mathematics Competition is held at universities accross North-America on the first Saturday in December of each year.
The contest is written, by undergraduate students, in two 3-hour sessions. In each session, students are given 6 problems to work on.
These problems are quite difficult, and most students are not able to solve more than one or two in the allotted time.
Prizes are awarded to the top 25 students.
For more information, visit the Putnam Competition website at
William Lowell Putnam Competition


References

Some Putnam problems from previous years along with solutions to some of the problems can be found at the following sites:
Kiran Kedlaya's Putnam Archive
The Art of Problem Solving site
John Schole's site

The Mathematical Association of America has published three collections of Putnam Competition Problems and Solutions:
The William Lowell Putnam Mathematics Competition - Problems and Solutions: 1938-1964, by Gleeson, Greenwood and Kelly.
The William Lowell Putnam Mathematics Competition - Problems and Solutions: 1965-1984, edited by Alexanderson, Klosinski and Larson
The William Lowell Putnam Mathematics Competition 1985-2000: Problems, Solutions and Commentary, by Kedlaya, Poonen and Vakil.

Some other good books on mathematical problem solving include:

Problem-Solving Stategies, by Arthur Engel
Putnam and Beyond, by Titu Andreescu

Problem Solving Through Problems, by Loren Larson
The Art and Craft of Problem Solving, by Paul Zeitz
The Green Book and the Red Book of Mathematical Problems, by Kenneth Hardy
Books by Ross Honsberger (for example, Mathematical Morsels)
Books by Martin Gardner (for example, The Unexpected Hanging)
Books by George Polya (for example How to Solve It)


For a summary of the University of Waterloo's results in the Putnam Competition, visit
Waterloo's Putnam History