Andrea Lavinthal and Jessica Rozler met as freshman journalism students at Syracuse—"we were in different social circles but all the same classes," Lavinthal recalled, relaxing at the Library Bar after leaving the Cosmopolitan office, where she's a content editor for the magazine's Sirius programming. After graduating, the pair wanted to work together on a book project, and took a look at various features they'd written for the school paper. A feature on hookups seemed "more relevant post-graduation than we'd ever thought it would be," she recalled, and that led to The Hookup Handbook: A Single Girl's Guide to Living It Up. Their initial attempts to find an agent failed, but they did score a meeting with editors at Simon and Schuster, at which point Rozler (who works as a production editor at Fairchild Books) looked up the agent for The Metrosexual Handbook, Adam Chromy. 24 hours after they contacted him, they had an agent—who got several other publishers to bid on the book before it landed at Simon Spotlight.

Their latest book, Friend or Frenemy?, described as "a guide to the friends you need and the friends you don't," has just come out from Harper—but before that, Lavinthal admitted, they had tried writing a novel together. "It just wasn't working," she said of the year they spent on that project; one day she turned to Rozler and asked, "Do you like this book?" Rozler mustered up an "it's all right," and they knew it was time to move on, keeping a few of the ideas they'd developed and reworking them into another lifestyle handbook. The pair tend to work from outlines, then take on individual chapters "until we can't look at it anymore and switch," Lavinthal said. "I'll get half a list done and tell Jessica to finish it." Rozler nodded, adding, "Anything scatological is probably me."

Do they have any good frenemy stories of their own to share? "I think I've weeded out most of the bad ones by now," Rozler said. "I think I have a lot more friend drama," Lavinthal agreed. She admitted that she'd had to "dump" a frenemy a while back; "I did it in the most passive-aggressive way," she said, "but I really needed a break from her."

"You think she's going to figure out that you're talking about her..." Rozler started to ask.

"...in every interview?" Lavinthal laughed, flipping through a small stack of magazines with recent mentions of the book. "I didn't talk about her in US Weekly, though, and that's the interview she's most likely to see."

What's next? Rozler allowed as how they were "kicking around some ideas" for their next project. "One more handbook," Lavinthal clarified, "and then it's time for novels, whether we do it together or separately."