Q My husband and I are in our early 40s. We are debt-free. We've lived our lives with the plan of paying off our mortgage as soon as possible. The importance of this idea was stressed to us with the advice of my father, who paid off his mortgage in less than 10 years.

We accomplished our goal before we both reached 40. We definitely took the safe road by paying down our mortgage at every opportunity when we could have enjoyed nicer cars, nicer vacations, etc. Now we are reaping the benefits of our dedication to this goal. We feel we can breathe easier than most in these tough economic times. We are not risk takers and are now concentrating on saving for retirement. We have all of our money ($80,000) in savings, not trusting the market. Can you recommend any other ideas to further our savings goals for retirement that are on the "safe side"?

THERESA, MINNEAPOLIS

A Congratulations on your discipline and savings strategy. It's terrific. In thinking about your question, I realized the best advice I could give is for you to pick up a copy of "Worry-Free Investing" by Zvi Bodie and Michael J. Clowes. Bodie is a leading finance professor at Boston University. Clowes is editor at large at Pensions & Investments, a trade publication.

The book was published in 2003 in the wake of an earlier bear market in stocks. Yet it remains a book for the times. After all, many savers in retirement plans are coping with the aftermath of two bear markets and two recessions in a mere eight years. Instead of asking the popular 1990s question, "How much money will I make?" investors are wondering about the more fundamental financial question, "How much can I afford to lose?" Their basic message fits in with your question.

What's the answer? Their preferred investment for long-term retirement savings is U.S. government inflation-protected securities. You don't have to worry about default with these fixed-income securities. They preserve the purchasing power of a dollar against the ravages of inflation, the enemy of long-term savers.

Think about it: $100 loses about a third of its value over two decades even at a modest 2 percent inflation rate. Of course, you'll take a lower payout on your savings in exchange for the inflation protection, but it's worth it.

U.S. inflation protected securities come in two flavors. First is Treasury Inflation Protected Securities, better known as TIPS. The other security is the savings bond called the I-bond. TIPS are best suited for tax-sheltered retirement savings plans. Like all savings bonds, the earnings on I-bonds are tax-deferred by definition. Of course, the authors deal with other conservative investment choices, but the core of their approach is government-backed inflation protected securities.

That said, they aren't stock-phobic -- and I certainly am not. They'd just prefer that individuals roll the stock market dice only after taking care of their baseline financial goals.

Chris Farrell is economics editor for American Public Media's "Marketplace Money." Send questions to cfarrell@mpr.org.