On his gonzo CNBC show "Mad Money," James Cramer flings stock picks with abandon, but in his new book, "Stay Mad for Life: Get Rich, Stay Rich (Make Your Kids Even Richer),"he offers well-considered advice on the building blocks of a prosperous life. He spoke with NEWSWEEK'S Daniel Gross.

You rail against credit cards and are a big proponent of thrift.
The recklessness with which people approach spending makes it very difficult to get rich. People will buy five DVDs from Disney instead of one share of Disney. They should do the opposite.

One of your rules for 401(k)s is that people shouldn't buy stock of their own company. Why?
I've seen too many 401(k)s that were 100 percent in the company's stock, and it's just devastating when it falls. Diversification is the only free lunch.

Investors can have a problem diversifying 401(k)s because of limited options. Many plans don't offer international funds.
This steams me. These human-resources people will keep you in the poorhouse. Who are they to take off the option that has been the best performer for the last 10 years?

So what do you think of the just-launched Fox Business Channel?
Candidly, I don't know how much room there is. It's not politics. It is a niche. That said, I like competition.