To many people, the image of a nuclear family in a stand-alone house with a green lawn and white picket fence still represents a fulfillment of the American dream.

However, this ideal is relatively new within a broader history of housing and development in the U.S. It’s also a goal that has become increasingly unattainable.

You’ve seen the ads in your neighborhood. They’ve flashed across your television and buzzed your phone to life at odd hours. The slogans and phone numbers might change, but the pitch is the same: “We buy houses for cash.”

Thousands of real estate investors across the country use a variety of techniques to find potential sellers and plan their next deal.