Upfront teacher's edition.

• Author: Zack, Ian

Facebook's long-awaited initial public offering, expected later this year, is generating lots of buzz, in part because 27-year-old founder Mark Zuckerberg is about to join the ranks of the world's richest people. For Upfront, it presents the perfect opportunity to explain I.P.O.s, the stock market, investment banks, and more. Our cover story also looks at how the social-networking company makes money--by selling vast amounts of user data--and how it's changed lives, both here at home and for protesters seeking democracy in the Middle East.

The U.S. military officially bars women from combat, but in Afghanistan--where the front lines are undefined and the enemy can be anywhere--the reality is different from the rule. We examine how the wars in Afghanistan and Iraq have redefined the roles of female soldiers on the battlefield.

This summer, Seattle will join the growing list of U.S...