For the love of money.

According to Sting, when I interviewed him in 1996, there’s no other reason to bring a band back from the dead. Yet one must assume that Sting”who’s had a gold and platinum solo career for more than three times the seven years he was a member of The Police”had more than money on the brain when he reunited the band in 2007, after more than two decades of inactivity, for a thirtieth anniversary world tour.

Think about it: If Diana Ross can try to regroup with Mary Wilson and Cindy Birdsong (though she ended up with two ’70s Supremes with whom she’d never actually performed and possibly never even met until minutes before the ill-fated 2000 “reunion” was announced), why can’t all other former bandmates get along”or at least get back together. Are you listening, ABBA? Though a musical reunion of Sweden’s fab four, or the UK one from the ’80s (that would be The Smiths), remains as unlikely as a resurgent Rubik’s cube or Carter Country, in recent years, we’ve seen a number of bands”from the Pixies to Yaz to the “classic” original line-up of Duran Duran”come together again.

Some did it for the love of money, some because of fading solo careers and some because as we get older those nostalgic impulses become harder to ignore. One imagines the latter must have been a big part of the reason why rich solo superstar Robbie Williams mended fences last year with Take That”who’d already reformed in 2005, nine years after breaking up”and participated in Progress, their first album together in fifteen years. This month, the original Take That will hit the road with Pet Shop Boys.

On May 10, The Cars, who haven’t released a new studio album since Ronald Reagan was in office, will drive their act into this millennium with Move Like This and a ten-date reunion tour that begins in Seattle on the day of the album’s release. They won’t be the only ’80s throwbacks on the road in the coming months. Bobby Brown recently said that the off-and-on-and-off-and-on-again New Edition has a new album and tour in the works. Perhaps they should join New Kids on the Block (who’ll be performing live this summer with Backstreet Boys) and soon-to-be summer tour mates Tiffany and Debbie Gibson for a Monsters of ’80s Pop package.

Then there’s Soundgarden, the band who along with Nirvana and Pearl Jam created grunge’s holy triumvirate in the early ’90s. They split in 1997, and although Chris Cornell had success as a member of Audioslave, his solo career never quite caught on. Can grunge thrive in 2011? We’ll find out when the Seattle band, set to tour in July, releases its work in progress later this year, but the odds might be stacked against them.

With a few exceptions”the Eagles, Steely Dan and Take That, whose Progress has enjoyed massive UK sales”reunited bands generally have had more success with comeback tours than with new music. Roxy Music, the Pixies and Psychedelic Furs have been back together for years, but neither band has released new albums. And Blondie, whose Panic of Girls is due on July 4, had middling US success with 1999’s No Exit and 2003’s The Curse of Blondie (though the former did produce the No. 1 UK single “Maria”).

In 2008, New Kids on the Block, whose reunion tour year featured Lady Gaga as an opening act, got off to a good start with The Block (first-week sales: 100,000), but the album failed to go gold in the US. The Cars’ new single, “Sad Song,” hasn’t gone higher than No. 37 on Billboard’s Rock Songs chart since its March 1 release, which doesn’t bode too well for the buzz-free Move Like This. Meanwhile, Duran Duran’s nostalgia value makes the group a huge touring attraction, but the new albums featuring the original line up (minus guitarist Andy Taylor) have sold only modestly.

But with album sales continuing to free fall anyway, it might not even matter. Releasing new music keeps the bands from being strictly oldies acts, and if the love of money is their bottom line, most of them are getting exactly what they’re after on the road.