"A First Course in Probability" (9th Edition) by Sheldon Ross is a comprehensive introductory textbook that covers the fundamental concepts and principles of probability theory. Designed for undergraduate students, the book presents a clear and accessible approach to topics such as random variables, probability distributions, expected values, and the law of large numbers. It includes a variety of examples and exercises to reinforce understanding, along with applications to real-world problems. The 9th edition features updated content, improved clarity, and additional exercises, making it a valuable resource for students in mathematics, statistics, engineering, and related fields. The book aims to build a solid foundation in probability, equipping readers with the tools necessary for further study in statistics and data analysis.