The first edition of Schaum’s Probability and Statistics by Murray R. Spiegel appeared in 1975, and it has gone through 21 printings since then. Its close cousin, Schaum’s Statistics by the same author, was described as the clearest introduction to statistics in print by Gian-Carlo Rota in his book Indiscrete Thoughts. So it was with a degree of reverence and some caution that we undertook this revision. Our guiding principle was to make changes only where necessary to bring the text in line with the emphasis of topics in contemporary texts. The extensive treatment of sets, standard introductory material in texts of the 1960s and early 1970s, is considerably reduced. The definition of a continuous random variable is now the standard one, and more emphasis is placed on the cumulative distribution function since it is a more fundamental concept than the probability density function. Also, more emphasis is placed on the P values of hypotheses tests, since technology has made it possible to easily determine these values, which provide more specific information than whether or not tests meet a prespecified level of significance. Technology has also made it possible to eliminate logarithmic tables. A chapter on nonparametric statistics has been added to extend the applicability of the text without raising its level. Some problem sets have been trimmed, but mostly in cases that called for proofs of theorems for which no hints or help of any kind was given. Overall we believe that the main purpose of the first edition—to present a modern introduction to probability and statistics using a background of calculus—and the features that made the first edition such a great success have been preserved, and we hope that this edition can serve an even broader range of students.