This book offers a gentle yet rigorous introduction to probability theory, with a special focus on finite probability spaces. Drawing inspiration from card games, casino games, mahjong, and two-up, it also delves into real-world applications such as weather forecasting, lotteries, hereditary diseases, and PCR virus testing. Discover which casino game gives you the best chance of winning and which one offers the worst odds. Assuming only a high school mathematics background, this book is an excellent resource for both students and teachers, providing clear explanations and engaging examples. The technical material is lightened with entertaining stories, such as how someone became a millionaire by spotting a flaw in a national lottery and how another person helped fund a war using winnings from a well-known card game he invented. Engaging and informative, this book is perfect for anyone looking to deepen their understanding of probability theory while enjoying some fascinating anecdotes along the way.