George G. Roussas 
Introduction to Probability [PDF ebook] 

Roussas’s Introduction to Probability features exceptionally clear explanations of the mathematics of probability theory and explores its diverse applications through numerous interesting and motivational examples. It provides a thorough introduction to the subject for professionals and advanced students taking their first course in probability. The content is based on the introductory chapters of Roussas’s book, An Intoduction to Probability and Statistical Inference, with additional chapters and revisions.* Written by a well-respected author known for great exposition and readability* Boasts many real world examples* Pedagogy includes chapter summaries, tables of distributions and formulas, and answers to even-numbered exercises