By Elysa Gardner, USA TODAY

The key words in the title of the Backstreet Boys' new greatest-hits collection, according to the group's members, are Chapter One. "This represents the end of one phase of our career — and the beginning of another," says Kevin Richardson of the 13-song The Hits: Chapter One, due in stores Tuesday. Richardson and his bandmates — Nick Carter, Howie Dorough, Brian Littrell and A.J. McLean — have packed a lot of activity into the final weeks of their first phase, even while confronting personal ordeals.

Shortly after McLean returned to the group following a highly publicized stint in rehab, Backstreet lost a crewmember, carpenter Daniel Lee, who had been aboard Flight 11, the first plane to plunge into the World Trade Center on Sept. 11. The Boys canceled the last date on their 2001 tour to take part in the Concert for New York City, Oct. 20's benefit for victims of that attack. The next day, they took part in the United We Stand: What More Can I Give benefit in Washington, D.C.

Then it was back to New York for a flurry of TV appearances promoting The Hits. The anthology features one new track, Drowning, which Richardson notes is faring better on radio than any single from Backstreet's most recent CD, Black & Blue. Despite selling more than 5 million copies domestically, that album was considered a commercial disappointment after the smash success of its predecessor, 1999's nearly 12-times-platinum Millennium.

Drowning is the sort of lilting, midtempo ballad that is typically embraced by adult top 40 and adult-contemporary radio — formats more popular with thirty- and fortysomethings than the teenyboppers who put Backstreet on the map. Of course, the band members, who joined forces nine years ago, have also matured. Richardson, the eldest, turned 30 on Oct. 3 and has been married since June 2000. Littrell celebrated his first wedding anniversary last month.

"When we started out, we couldn't wait for the day when we had an adult-contemporary audience," Dorough muses. "Now that we have one, we're hoping that we don't lose the teen market! We want our music to be for everybody."

Richardson concurs. "Yes, we initially had a very young fan base. But so did Michael Jackson and Janet Jackson and Madonna, and they're still appealing to the young and the old, which is what we hope to do now."

Dorough says that while Black & Blue "didn't do exactly what we were hoping it would, we learned a lot from it. It was the first time that all five of us wrote music together. Some stuff could have used a little more work, but we were under a time crunch. Next time, we'll concentrate on not rushing."

Richardson predicts that the Backstreet Boys' next studio album — which the group plans to begin sessions for in January or February — will feature "a more organic sound. On the ballads, we've talked about using more live strings, live bass, piano, acoustic guitar. For the uptempo songs, we've talked about going in more of a funk direction." Backstreet is also interested in working with hip-hop-savvy producers such as Jimmy Jam and Terry Lewis and Jermaine Dupri, whom Richardson has been in discussions with.

The Boys realize that becoming men means focusing on new priorities outside the group. "Brian and I have our wives, and we'll eventually have our own families," says Richardson. There are also individual career considerations. McLean wants to continue working on solo material. Richardson has been auditioning for film roles, he says, and both he and Littrell have started production companies. And Carter, the baby Backstreet Boy, "just wants to do everything," Richardson muses.

"The Backstreet Boys have always been five individuals who come together," says Richardson. "As we're getting older, we're acting even more as individuals, and it's a challenge to stay on the same page. But as long as we can continue to make good music, that challenge will only make us stronger."