Call it a case of the 17-year itch. Boston's hard working, housepartying J. Geils Band played together for 17 years before a bitter breakup. Now, another 17 years later, they've reunited.

"Its like we had a 17-year sleep", singer Peter Wolf says. "Does the name Rip Van Winkle mean anything to you?" guitarist Jay Geils chimes in.

Geils' crack provokes laughter from the other band members, all seated in a Charlestown rehersal studio. It's the end of another day spent preparing for the sold out Tweeter Center launch on Wednesday and Thursday of their much anticipated reunion tour. The atmosphere in the dark, equipment filled room is downright merry. The jokes and banter fly back and forth. The band members appear to enjoy each other's company. Which is noteworthy.

Not so long ago, they seemed enmeshed in an insolvabe feud. The bad feelings surfaced after the J. Geils Band, a beloved touring act of the '70s, finally achieved a commercial breakthrough in the early '80s with its first and only No. 1 single, "Centerfold", and its Top 10 follow up, "Freeze Frame". Officially, the breakup was attributed to the standard "creative differences". Unofficially, the talk was of a clash of wills between motormouthed frontman Wolf and keyboardist and principal songwriter Seth Justman.

After the split, Wolf forged ahead, making critically praised but weak selling solo albums, most recently "Fool's Parade" on Mercury. Geils and harmonica man Magic Dick formed their own rootsy band, Bluestime. Bassist Danny Klein put together a group called Stone Crazy after a six year stint as a cook. Justman and drummer Stephen Jo Bladd virtually disappeared from view.

Meanwhile, the group's loyal fans kept hoping for a thaw in the cold war. There were several attempts to patch together a reunion, but they went nowhere - including an offer to play at the opening of the Fleet Center. Enter John Baruck, former manager of another popular '70s touring band, REO Speedwagon. "He was the guy who started hitting on us last year", Geils says. "He said, 'Don't worry about the radio or records. Just play the show. People will want to hear it'. And when our interest in his proposal started to dwindle, he said 'I'm not going away. I want to make this happen.' And here we are."

A PAST LIFE J. Geils Band frontman Peter Wolf sings during a 1975 concert in Providence.

"What is was", Wolf picks up, "was that previous ideas about getting us together always got complicated with talk about long range commitments and schedules and records. John made it very simple. He said, 'Block out part of the summer to play these shows and that's it, take that one step and we'll talk about the future after'."

All the former Geilsmen agreed to give it a try - except Bladd. "We were all disappointed," says Wolf, who true to his frontman role, dominates the conversation. "We wanted to see a reunion with all the original members. But for emotional and personal reasons, (Bladd) didn't want to get into this whole whirlwind. His life had moved in other directions. There were no bad vibes, no hostility."

"Doing a J. Geils show is not like doing a show with the Eagles or Crosby, Stills, Nash & Young. It requires a commitment of mind and body." "We're a very athletic band", Klein adds. Justman immediately had a replacement in mind: Sim Cain, drummer with the hardcorps punk Rollins Band.

"The offer came as a complete surprise", says Cain. "But I didn't have to think much at all about accepting. Actually, there are more similarities than you might think between the Rollins Band and the Geils Band. Both bands exhaust their audiences. Stamina is needed."

But before Cain entered the picture - and before a summer tour was agreed to - the estranged band members first needed to get reacquainted, musically and personally. "In January, we got together in a secret locale to see how everybody felt," Wolf recalls. "Some of us hadn't seen each other in years."

"Dick and I started talking and pretty soon we got started playing a blues shuffle thing, 'Be Careful', an old song by (Chicago bluesman) John Brim." "Which we had recorded on 'Hotline'," Geils notes. "After that we did a couple of tunes by (harmonica legend) Little Walter," Wolf continues, "and then slide into 'First You Look At The Purse' and 'Looking (For A Love)'."

"Then I started calling out songs. 'Sanctuary.' ' Love Stinks.' Then I started the rap on 'Musta Got Lost', and everybody..." "Everybody left!" injects Klein. All present crach up, including Wolf. "We broke for lunch and when we came back Pete was still going."

"One of the things that did break the ice," Wolf picks up when the laughter ends, "was that I was sitting there smoking some Camel cigarettes and that led to a discussion about Frank Sinatra. There was a bottle of booze that I happened to have and Jay said, 'Hey man'." "Just happened to eyeball it," Geils says grinning.

"So there was a run made to the package store down the street," Wolf says. "Before we knew it, it was cocktail hour. I have to say the Geils Band does quite better when we serve the five 'oclock angels." No one is smoking or drinking anything but bottled water at the moment. But the scent of male camaraderie is thick in the room.

It's evident that these veterans of the '60s and '70s haven't turned into politically correct New Agers with the onset of middle age. "When we started playing that first day," Magic Dick (Salwitz) says, "I thought 'Jeez, it feels like we never stopped'. But after being away from out material for so long, there was a freshness to it. And that freshness is coming out even more now. Bringing Sim into it, there's an energy and drive that's very reminiscent of what we used to do. It may even be more intense."

"Take it from me," Cain says on cue. "This band has never sounded so good." His quip is greeted with hooting and more mirth. Questions about the future of the J. Geils Band are politely deflected. There is no specific plan to write new songs, no recording deal in the works, no agreement to do anything beyond this summer tour. All that will be addressed in time.

"It's the Never Say Never tour," Justman says. "It's also the Looking Forward tour. Here we are in the same room playing music, having a great time, revving up the J. Geils furnace. Where will it all go? We don't know, but we're going to find out."