When one of the biggest rock bands in history comes to you and asks you to be its new lead vocalist, you say, “Yes.”

Without hesitation.

That’s the conventional wisdom, anyway.

But when the members of Styx made that proposal to Canadian rocker Lawrence Gowan in 1999, he needed some time to think.

Gowan had achieved unequivocal solo success in Canada and England (Gold records, Canuck Grammys, command performances, etc.) and he wasn’t sure he wanted to hitch his wagon to Styx’s star.

“When I speak of it in the United States,” Gowan said in a phone interview, “it seems almost irrelevant. My records were never released here and so the assumption is: ‘Are you kidding? When a band like Styx asks you to join, you don’t give it a second thought! There’s nothing to think about!’ Well, there was something to think about.”

Fortunately for Styx, an English publicist had gifted Gowan with a reality check.

“She had this crystal ball that proved pretty accurate,” she said. “She said, ‘Look, you just turned 40 years of age. Looking at the way the music industry is going, the most likely scenario for you is that you’re going to wind up joining a band.”

Ultimately, Gowan decided to disregard whatever misgivings he had and go with his gut.

“At a certain point, you have to think, ‘Stars are sort of aligning in a way that they’re trying to tell me something,'” he said. “I don’t think it’s a bad way to go. You can buck against that all your life, but it might end with you saying, ‘Well, at least I stuck to my guns and my principles and it led me straight to the gutter.'”

It’s impossible to say where Gowan would be now if he’d turned down Styx’s offer. But we saw what happened to the music industry in the years after he accepted it: It ceased to exist as we knew it.

Styx perform June 18 at the Foellinger Theatre.

When lead vocalists depart major rock bands, the remaining members have to decide whether to recruit a soundalike or to go off in a bolder, more precarious, direction.

Gowan said he has never attempted an impersonation of Dennis DeYoung, Styx’s founding vocalist, and no one in the band has ever asked him to do one.

Gowan was long ago embraced by much of the band’s fanbase, but there remain a few stragglers who say they can never fully accept Styx without DeYoung.

That doesn’t offend Gowan.

“There’s a paradigm I’ve tried to hold onto whenever anyone says, ‘I can’t accept this band,'” he said. “I think, ‘You know something? You’re absolutely entitled to that feeling.’ Because it’s a subjective thing. If your musical life is entirely connected to that specific lineup and that specific time, you’ll never accept that.”

Gowan recalled experiencing similar emotions after Phil Collins succeeded Peter Gabriel as lead vocalist of Genesis.

“I remember Phil Collins stepping up to the mike, and I am thinking, ‘This is wrong,'” he said. “And preparing myself to go, ‘I’m not going to like this.’ And there I am, 15 minutes later, going, ‘Holy (expletive)! That was great!’

“They both kind of had the same spirit,” Gowan said. “There was something in the spirit that was intact.”

Gowan and Styx also share the same spirit.

For Gowan, both incarnations of Genesis are important, and he loves it when fans say the same thing about both incarnations of Styx.

“The greatest compliment I hear,” he said, “is when someone says, ‘I saw the band in 1981 and I saw the band tonight, and you are just as good as ever.”

In the years when the bottom was dropping out of the music business, a lot of formerly well-paid musicians worried that the bottom was about to drop out of their livelihoods.

It was during this tumultuous time, Gowan said, that Styx came up with a mantra, of sorts: flexible and adaptive.

“J.Y. (Young) used that phrase so often,” he said. “Whenever anything was a challenge to him or was a challenge to his sensibility, he would use that phrase: ‘Flexibility and adaptability! We must adapt to move on.’

“That credo is what got me into the band in the first place,” Gowan said. “Every time we fell back on that phrase, it led us another step forward.”

Gowan recalled how one aspect of the digital revolution dawned on the band.

“We started seeing these little video cameras at shows,” he said. “It wasn’t quite the smart phone era yet, and it was like, ‘Should we stop that or let it go?’ Sometimes they’d stop it, and other times someone would say, ‘I saw that they put that on the internet the next day and thousands of people were saying, ‘I love this. I want to see Styx.’ So, maybe this is good.'”

In the 20th century, bands made their money from recordings. In the 21st century, music was freed from sellable discs and fewer people were willing to pay coffer-lining fees for it. So bands were forced to hit the road harder than they may have been naturally inclined to hit it.

This made life more difficult for bands, but Gowan said he sees one improvement over the former business model.

In the late 20th century, there were many musical acts that couldn’t come close to matching the quality of their recordings in the live setting.

Now, most of them have no choice.

In a world where musicians’ livelihoods depend on their ability to perform live, Styx excels.

Gowan said he believes a rock show is the best entertainment there is.

“To feel this thing that happens at a rock show …” he said. “We still can’t explain what it is. It’s the best form of entertainment I have come across as far as long-lasting effects afterwards.

“There are fantastic movies, fantastic plays,” Gowan said. “But a rock show is an experience that will stay with you. That’s a wonderful thing to be connected to every day.”

The state of the music business these days depresses some folks who got a taste of the gilded age.

But Gowan said the members of Styx have never been anything but grateful.

“It comes up in the dressing room,” he said. “It honestly does: ‘You know how lucky we are to still be doing this? And have people who are, like, one half our age comprising one half of the audience out there screaming and singing along?’ That’s a pretty fantastic thing.”