Davin Lamm is passionate about fishing. On the living-room wall of his Philadelphia home are framed photos of his prized catches surrounding what appears to be a 45-inch-wide aquarium, with tropical fish swimming lazily about, accompanied by bubbling sounds. This can all change, though, at the flick of a remote, because what seems to be an aquarium is a flat-screen television, and the coral-reef scene is provided by an animated DVD screen saver.

The real estate bug bit Karen Brodie a few years ago. She left her desk job as an accountant with Fidelity Investments in 2001 and teamed up with a cousin to buy a single-family house in the Boston suburb of Dorchester for $98,000. After spending $50,000 to upgrade the house, the pair sold it a year later for $278,000. Now Brodie and her cousin have expanded their operation to include two pricier three-unit buildings in Dorchester and two three-family units in Rhode Island. With the Dorchester properties now up for sale, the pair could turn a profit of between $500,000 and $800,000 in little more than a year.

Across the country, thousands of people like Karen Brodie are chucking their day jobs to become real estate investors. And why not? The nation is experiencing a boom in property values that has seen the median price of an existing home rise 10% in the past year; 37 areas saw prices jump by at least 15%. Thanks to leverage, which lets you buy a property for a fraction of its cost, you can double your money in a flash.

Question: I am buying a new home. Do I need title insurance?

-- Virginia, Dunn Loring, Va.

Virginia: Yes, Virginia, assuming that you're financing this home, you do need title insurance. In fact, your lender will insist on it -- and you'll have to pay. The policy protects the lender (but not you) should there be any claim on the land from former owners -- say a divorced woman whose ex-husband forged her signature on a quit-claim deed, a mechanic's lien from an unpaid subcontractor or a long-lost heir. It's a good idea to get a separate owner's title-insurance policy to protect yourself, too, because such claims can emerge years after you've settled in, remodeled your basement and put in the petunias. Should anyone ever lodge a claim to your property, the insurer will cover the costs of any legal proceedings and settlement amounts. Coverage lasts as long as you own the property.

Question: How do you know when there is a real-estate bubble? What do you measure, what factors are involved and how do you calculate it?