It's also how the rich get richer. If you have enough safe assets, if you have enough

treasury bills to live on for three years or five years or better yet a decade, you're

not going to panic when the rest of your assets, the rest of your holdings, the risky assets

and stocks that you own, fall by 10 to 60 percent. You're not going to pull the trigger

and sell those at the bottom.

I'm Mary Long and that's William Bernstein, financial theorist, neurologist and bestselling

author.

Our very own Robert Brokamp caught up with Bernstein to talk about the psychology of investing

in the weighty influence of crowds, how to test a financial advisor, the best deal in

retirement planning, and what's changed in the two decades since Bernstein first wrote

the investing classic, the four pillars of investing, lessons for building a winning portfolio.

The Motley Fool was founded in 1993 by two brothers and their friend who believed that

with enough effort and dedication, most people could learn to manage their finances on

their own.

They might be better off for doing so, given how poorly Wall Street and the typical local

stock broker often treated the individual investor.

It occurred to me that around the same time, maybe a few years earlier, your life was

kind of taking a similar turn. You were a practicing neurologist who was just beginning what

would become a whole new career as an author of several well-respected books about investing

in financial history as well as becoming the principal in a wealth advisory firm.

So tell us how that career switch happened.

Well, around that time, a generation ago, I realized that I lived in a country that didn't

...