In December 1989, NBC had a pilot nobody wanted. "The Seinfeld Chronicles" had tested as one of the worst pilots in network history, the president of entertainment called it "too New York, too Jewish," and Fox had already passed. The show was dead. Then a specials executive named Rick Ludwin canceled a Bob Hope special on his own budget and used the money to order four more episodes, the smallest sitcom order in American television history.

But what if he doesn't? What if Ludwin lets the pilot die the way everyone at NBC expected? What happens to Larry David? What happens to the next 35 years of American comedy? And does the last great shared audience in American television history ever exist at all?

On December 10, 1996, Apple was months from bankruptcy and out of options. Two men flew to Cupertino to pitch their software as the company's last hope, Jean-Louis Gassée and Steve Jobs. Apple picked Jobs and used the software he brought with him to build the iMac, the iPod, the iTunes Store, and the iPhone.

But what if Gassée hadn't phoned it in? What if Apple picked the other guy and Steve Jobs never walked back through that door? What happens to Apple? What happens to the smartphone? And does the 21st century we're living in show up at all?

On August 8, 1974, Richard Nixon announced his resignation rather than face near-certain impeachment and removal. Barry Goldwater told him he had 15 votes. He needed 34. So he quit. But what if he didn't? What if Nixon told Goldwater to go to hell and forced the United States Senate to remove him? The trial would have been the biggest television event in American history, playing out during a midterm election, with a president who still controlled the military, the intelligence agencies, and the nuclear codes. What happens to the country? What happens to the Republican Party? And does the politics of grievance that defines America right now show up 40 years earlier?