It's not that he's just not that into you-it's that there aren't enough of him. And the numbers prove it. Using a combination of demographics, statistics, game theory, and number-crunching, Date-onomics tells what every single, college-educated, heterosexual, looking-for-a-partner woman needs to know: The man deficit is real. It's a fascinating, if sobering read, with two critical takeaways: One, it's not you. Two, knowledge is power, so here's what to do about it.

The shortage of college-educated men is not just a big-city phenomenon frustrating women in New York and L.A. Among young college grads, there are four eligible women for every three men nationwide. This unequal ratio explains not only why it's so hard to find a date, but a host of social issues, from the college hookup culture to the reason Salt Lake City is becoming the breast implant capital of America. Then there's the math that says that a woman's good looks can keep men from approaching her-particularly if they feel the odds aren't in their favor.

Fortunately, there are also solutions: what college to attend (any with strong sciences or math), where to hang out (in New York, try a fireman's bar), where to live (Colorado, Seattle, Man Jose), and why never to shy away from giving an ultimatum.