Daniel Crosby draws on psychology, neuroscience, and behavioral economics to build a comprehensive model of why investors consistently make decisions that harm their long-term returns, and what systematic changes can counteract these tendencies. The book is organized around four primary behavioral risk factors — ego, conservatism, attention, and emotion — each of which produces predictable, exploitable errors in investment judgment. Crosby explores how overconfidence leads investors to over-trade and under-diversify, how status quo bias causes dangerous inertia, how media and recency bias distort perception of risk and opportunity, and how fear and greed create the buy-high, sell-low patterns that destroy wealth across market cycles. Crucially, Crosby goes beyond diagnosis to prescribe behavioral and structural solutions: rules-based investing, diversification requirements, accountability structures, and the deliberate slowing of decision-making. Unlike many behavioral finance books that stop at identifying biases, this one is firmly oriented toward practical portfolio construction. Written with depth and intellectual rigor, it is essential reading for serious investors who want to understand not just what to own but how to manage the internal obstacles to acting rationally.