What's the best book about the 4 percent rule?
In one paragraph
The Simple Path to Wealth by JL Collins. Collins's chapters on the safe withdrawal rate are the cleanest plain-English explanation of the 4% rule in print — including its limits (it assumes a 30-year retirement, not a 50-year one).
What this actually means
The 4% rule comes from the 1994 Trinity Study (Cooley, Hubbard, Walz at Trinity University), which back-tested withdrawal rates against US historical market data and found that withdrawing 4% of an initial portfolio annually, adjusted for inflation, survived 30 years in nearly every historical window.
Collins explains all of this in Simple Path to Wealth without the academic jargon. He walks through the assumptions: 60/40 stocks/bonds, 30-year window, US market history, no behavioral mistakes. He also explains the failure cases — early-retirement scenarios that need 50-year horizons should use 3.25-3.5% instead, and back-to-back bear markets in the first decade of retirement (sequence-of-returns risk) can break the rule even at 4%.
For the academic original, the Trinity Study itself is freely available — it's a 1998 AAII Journal article, easy to find online. The book version of the same logic is in The Bogleheads' Guide to Retirement Planning, but that's a denser read.
The Elements of Investing covers safe withdrawal rates in a shorter, more abstract way and is useful as the academic supplement.
For most readers: Simple Path is enough. Collins shipped a book that explains the 4% rule, its math, its failure modes, and what to do instead at the edges. That's the whole education in 286 pages.
