The important and fascinating subject of probability began in the seventeenth century through efforts of such mathematicians as Fermat and Pascal to answer questions concerning games of chance. It was not until the twentieth century that a rigorous mathematical theory based on axioms, definitions, and theorems was developed. As time progressed, probability theory found its way into many applications, not only in engineering, science, and mathematics but in fields ranging from actuarial science, agriculture, and business to medicine and psychology. In many instances the applications themselves contributed to the further development of the theory. The subject of statistics originated much earlier than probability and dealt mainly with the collection, organization, and presentation of data in tables and charts. With the advent of probability it was realized that statistics could be used in drawing valid conclusions and making reasonable decisions on the basis of analysis of data, such as in sampling theory and prediction or forecasting. The purpose of this book is to present a modern introduction to probability and statistics using a background of calculus. For convenience the book is divided into two parts. The first deals with probability (and by itself can be used to provide an introduction to the subject), while the second deals with statistics. The book is designed to be used either as a textbook for a formal course in probability and statistics or as a comprehensive supplement to all current standard texts. It should also be of considerable value as a book of reference for research workers or to those interested in the field for self-study. The book can be used for a one-year course, or by a judicious choice of topics, a one-semester course. I am grateful to the Literary Executor of the late Sir Ronald A. Fisher, F.R.S., to Dr. Frank Yates, F.R.S., and to Longman Group Ltd., London, for permission to use Table III from their book Statistical Tables for Biological, Agricultural and Medical Research (6th edition, 1974). I also wish to take this opportunity to thank David Beckwith for his outstanding editing and Nicola Monti for his able artwork.