About This Book

The Philosophy

"Avoid Stupid" is more than a title — it is the foundational principle that guides every investment decision at Marlowe Keynes. In a world obsessed with finding the next brilliant trade, we believe the greatest edge comes from disciplined avoidance of costly mistakes. The smartest investors are not those who find the most opportunities, but those who say no to the most temptations.

This book distills 50 core principles drawn from decades of real-world investing experience. Each topic represents a lesson learned not from textbooks, but from the crucible of markets — where patience is tested, conviction is challenged, and the difference between wisdom and recklessness is measured in decades, not quarters.

About Marlowe Keynes LLC

Marlowe Keynes LLC is an investment firm founded on the conviction that long-term ownership, deep fundamental research, and psychological resilience are the true engines of compounding wealth. We do not chase trends. We do not trade on noise. We build concentrated positions in businesses we understand deeply, and we hold them with the patience that compounding demands.

Our approach is rooted in the belief that the greatest risk in investing is not volatility — it is the permanent loss of capital caused by impatience, overconfidence, and the failure to maintain a margin of safety. Every position we take begins with one question: "What could go wrong?" Only after satisfying that inquiry do we ask what could go right.

About the Author

David L. Steinberg is the founder and principal investor at Marlowe Keynes LLC. With a career spanning decades in the financial markets, David has developed a philosophy that prizes discipline over brilliance, endurance over elegance, and quiet compounding over dramatic returns. His investment approach draws from the intellectual traditions of value investing while adapting to the structural realities of modern markets.