One of the most powerful and popular tools used in combinatorics is the probabilistic method. Describes current algorithmic techniques, applying both the classical method and the modern tools it uses. Along with a detailed description of the techniques used in probabilistic arguments, it includes basic methods which utilize expectation and variance plus recent applications of martingales and correlation inequalities. Examines discrepancy and random graphs and covers such topics as theoretical computer science, computational geometry, derandomization of randomized algorithms and more. A study of various topics using successful probabilistic techniques is included along with an Open Problems Appendix by Paul Erd?s, the founder of the probabilistic method.