Given the unpredictability of capital markets what level of withdrawal from a fund is safe over the long term? Bergen examines data from 1926 through 2005 to analyze a variety of withdrawal strategies to find a maximum withdrawal rate that would have preserved capital over a thirty year period. It's readable, well thought out. Bergen is "famous" in a relatively small circle for having come up with the "four percent rule". Although that rule is simplistic, the book is not and offers a variety of strategies for different circumstances. A very useful little book.