The Little Book of Common Sense Investing by John C. Bogle is a straightforward guide to passive investing. Bogle, the founder of Vanguard Group, advocates for low-cost index funds as the best long-term investment option for individual investors. He explains the benefits of diversification, the impact of fees on investment returns, and the importance of staying the course. This book is a must-read for those looking to simplify their investment approach and achieve steady, consistent returns.