Importance
Pattern Recognition
Richard O. Duda and Peter E. Hart, Pattern Classification and Scene Analysis, John Wiley & Sons, 1973.		*
This is one of the pattern recognition bibles.
B. D. Ripley, Pattern Recognition and Neural Networks, Cambridge University Press, 1996.		*
Excellent introduction and overview, contains a wealth of references.
Keinosuke Fukunaga, Statistical Pattern Recognition, Academic Press, 2nd Ed., 1990.		*
Learning Theory
C. M. Bishop, Neural Networks for Pattern Recognition, Oxford Univ. Press, 1995.		*
Very intuitive and easy to read.
V. Vapnik, The Nature of Statistical Learning Theory, Springer, 1995.
Significant, but rather elaborate.
Computer Vision
B. Horn, Robot Vision, MIT Press, 1986.		*
Probability Theory
Athanasios Papoulis, Probability,  Random Variables and Stochastic Processes, McGraw-Hill, 3rd Ed., 1991.		*
Painless introduction to the topic, but mathematically not the most rigorous.

The references above are labeled with importance:
* the reference is not required reading, but included for those who want to know more about the topic.
** strongly encouraged, but not required
*** required reading