Third Stage was the nexus point between what could have been the end of Boston, and an entirely new beginning.

Rushed into releasing a follow-up to their breakout 1976 self-titled debut, Tom Scholz was determined not to repeat the mistakes of 1978's Don't Look Back. When this third studio effort ended up taking eight long years, however, Boston's lineup began to fracture – and their frustrated label decided to sue.

"If I were a more ambitious person, I probably would have been upset about it," the late Brad Delp told Knight Ridder Newspapers in 2004. "As it turned out, my daughter was born in 1980, and that was a little while after we got off the Don't Look Back tour. So, I got to spend a lot of time watching her grow up."

Third Stage eventually arrived on Sept. 23, 1986, but not before long-time second guitarist Barry Goudreau, bassist Fran Sheehan and drummer Sib Hashian had split. That left guitarist Scholz and frontman Delp to lead a reworked lineup, even while Scholz continued to fight the lawsuit filed by Epic Records.

"Part of the whole trauma of going through that period is that I had to beat an injunction to release the album," Scholz told Goldmine in 2008. "They tried to block the release of Third Stage. I had to beat the lawsuit to even see anything from it. I had run up incredible legal fees."

Perhaps unsurprisingly, Third Stage is shot through with darker, more adult themes not previously heard from Scholz, who once again handled almost all of the instrumentation and composing while serving as producer for the sessions.

Listen to Boston Perform 'We're Ready'

"It is about a lot more than adulthood," Scholz added. "Adulthood is about being old enough to drink, have sex and get married. It is a different thing. I considered the next step when you are supposed to get a better car and buy a house, which isn't really what's important in life. The intent with the Third Stage message is when you cross over that point and really realize what is going on around you and that the rest of the inhabitants of the earth are what is important."

"Amanda," a track that he'd been working on as early as 1980, emerged as Boston's first and only chart-topping single, while "We're Ready" (No. 9) and "Can'tcha Say (You Believe in Me)/Still in Love" (No. 20) also reached the Billboard Top 40. Third Stage became Boston's second (and final) No. 1 album as well, going four-times platinum along the way. That provided plenty of momentum for a resulting tour, which then set the stage for Boston's next era.

Delp and Scholz were joined on the road by bassist David Sikes, drummer Doug Huffman and second guitarist Gary Phil, forming a lineup that remained solidly in place into the early '90s. "We turned a corner for performing at that point," Scholz told Goldmine. "It was the start of being technically really good live, as opposed to being really good in the studio. I don't want to take anything away from the guys who played in the '70s; they are all very good musicians, but it was a different time. You basically plugged in your amp and wailed away."

Pihl, who sat in on "I Think I Like It" from Third Stage, officially joined after a lengthy stint with Sammy Hagar that – as the fates would have it – included opening for Boston. Then, Hagar got the call to join Van Halen.

Scholz immediately got in touch with Pihl. "Hey, I heard you're out of a gig," Pihl remembers Scholz saying, in a 2015 talk with the Elgin Courier-News. "Why don't you come back here and help me finish the Third Stage album? There was one more song to be recorded. So I went back, and that was the end of '85, and I've been here ever since. ... Our last show with Sammy was Farm Aid 1 down in Champaign. I flew directly from Champaign back to Boston to start working with Tom. So, I wasn't out of work for a day. How lucky can a guy get?"

The Top 100 Rock Albums of the '70s