Ben Eisen runs the Personal Finance Bureau at the Wall Street Journal, and he's actually in the midst of writing a book about the rise of the American mortgage market.

You had these people who were starting families.

They needed bigger homes.

They didn't even have homes.

Some of the descriptions of what it was like for these GIs returning home at the time, they were living in church basements and chicken coops.

There was just such a demand for housing that they couldn't build fast enough.

That's Wall Street Journal editor Ben Eisen again.

You enter into a multi-year project not knowing if there's gonna be demand at the end of the line, or if you're gonna recoup your money.