What's the best book about compound interest?
In one paragraph
The Psychology of Money by Morgan Housel. The chapter on Warren Buffett — showing that 99% of Buffett's $80B+ net worth came after his 50th birthday because compounding only works on long time horizons — is the clearest single explanation of why compound interest matters that's been written.
What this actually means
Most personal-finance books mention compound interest in passing. Housel's chapter 'Confounding Compounding' makes it the central idea: Buffett's investing returns are good but not historically extraordinary. What's extraordinary is that he started investing at 10 and is still investing at 95. The 85-year runway is the alpha, not the stock picks.
The Simple Path to Wealth makes the same case differently. Collins shows the math: a 25-year-old who saves $500/month and stops at 35 ends up wealthier than a 35-year-old who saves $500/month until 65. Same total money saved; the early starter wins because of compounding. That single chart is the most-shared graphic in the FIRE community.
The Elements of Investing by Ellis and Malkiel covers compounding in a more academic frame — the chapter on the 'magic' of compounding includes the Rule of 72, the long-run S&P 500 numbers, and the contrast between simple and compound returns. Short and quantitative.
The Total Money Makeover has the most famous compound-interest chart in personal finance (the 'two friends' story showing the cost of waiting), though Ramsey uses unrealistic return assumptions. The lesson lands even when you correct the math.
Start with Psychology of Money. The Confounding Compounding chapter is 12 pages and worth the price of the book.
