Fleetwood Mac released their ninth album, Heroes Are Hard to Find, in the fall of 1974. Although it gave the band their first Top 40 hit in the U.S., it also led to yet another in the seemingly endless series of lineup changes that had dogged them since co-founding guitarist Peter Green quit in 1970. But it also resulted in Fleetwood Mac, which changed the course of their history.

Guitarist Bob Welch departed after Heroes was released, leaving the band in a state of flux that was compounded by the fact that they'd been in the middle of a long legal struggle with ex-manager Clifford Davis, who claimed he owned the Fleetwood Mac name and tried to prove it by sending a "fake" version of the group out on the road. Forced to find a replacement for Welch just as they settled things with Davis, Mac mainstays Mick Fleetwood, Christine McVie, and John McVie ended up adding two new members — and setting themselves up for a massive commercial breakthrough.

It all started, according to Fleetwood, with a trip to the supermarket. In a 1976 interview with Melody Maker, he recalled having a chance encounter with "a guy" he told he was searching for a new studio for the band's 10th LP. "He told me about a studio, Sound City in Van Nuys," said Fleetwood, whose tour of the facility included a fateful demonstration of the studio's gear: "They played me a tape of Stevie Nicks and Lindsey Buckingham which they had done a couple of years ago. At the time I made a mental note about them, and soon after made a phone call to them asking if they wanted to join."

Buckingham and Nicks were already a recording act in their own right, although their self-titled debut album had tanked after its 1973 release and Nicks was working as a waitress while they figured out their next move. "He was standing there grooving to this searing guitar solo and he needed a guitar player. That was as far as his thinking went," Buckingham later told Uncut of Fleetwood's first exposure to the pair. "I had to explain we came as a duo."

Accustomed to steering his own creative destiny, Buckingham was initially ambivalent about joining up with Fleetwood Mac. But, as Nicks told Uncut, the couple "were in total chaos" before receiving the offer and needed the stability — not to mention the money. "I said, ‘We can always quit,'" she remembered. "'They’re going to pay us $200 each a week, so we can save some money and leave in six months with a little nest egg if it doesn’t work.'"

Happily, the freshly minted fivesome meshed much more easily than Buckingham might have suspected, and set up shop at Sound City with producer Keith Olsen in early 1975, weaving together a set of songs that drew from pre-existing Buckingham/Nicks numbers as well as new material written by Christine McVie and a Buckingham/McVie co-write, "World Turning." As Buckingham told the Independent, although he and Nicks were junior members, they were given plenty of creative room to shine.

"Stevie and I had aspirations," he pointed out. "We hadn't given up. There was a lack of clarity about exactly what our role would be with Fleetwood Mac."

"It felt right. It was very quick," Fleetwood asserted in a 1976 interview with NME. "In fact, they joined the band before we'd even played a note. It was just right. We all met. We all liked each other and that was it. Rehearsed for 10 days and went in and made the album. That was it. It was just a great sense of circumstance."

While the new Fleetwood Mac clicked as a musical unit, the personal relationships between various members of the band were falling apart — Christine and John McVie's marriage was nearing its end, and Buckingham and Nicks were close to breaking up before they joined the lineup. Over time, both couples' demise would form a key component of the group's legacy (and help inspire their best-selling album), but in the short term, that air of uncertainty fueled a number of future classics.

One example is the Nicks composition "Landslide," which, as she explained to Performing Songwriter, she wrote during a trip to Colorado when Buckingham was rehearsing for a possible project with Don Everly. "This is right after the Buckingham Nicks record had been dropped. And it was horrifying to Lindsey and I," she laughed, "because we had a taste of the big time, we recorded in a big studio, we met famous people, we made what we consider to be a brilliant record and nobody liked it [...] I had gotten to a point where it was like, 'I’m not happy. I am tired. But I don’t know if we can do any better than this. If nobody likes this, then what are we going to do?' So during that two months I made a decision to continue. 'Landslide' was the decision."

Watch Fleetwood Mac Perform 'Rhiannon'

Nicks also contributed the standout track "Rhiannon," which she wrote shortly before joining Fleetwood Mac after reading Mary Leader's novel Triad. The book's story incorporates elements of the Welsh legend of Rhiannon, which Nicks unwittingly wove into the song even though, by her own admission, she didn't really know about it until much later.

"I didn’t know anything about Rhiannon when I wrote the song 'Rhiannon,'" explained Nicks. "I was just reading a paperback book, and the name Rhiannon came up and I loved it." Telling Buckingham and engineer Richard Dashut that she wanted them to go outside and record birds singing for a demo she was working on, she recalled, "Of course Richard and Lindsey looked at me like, ‘She’s really gone around the twist this time, huh?’ And I said, ‘Don’t you think that Rhiannon is a beautiful name?’ Lindsey said, ‘Yeah, it is a beautiful name.’ Three months later, we joined the band and I played it on the piano in my little simple way of playing ... they loved it."

That sort of creative serendipity seemed to surround the sessions for the new album, which wrapped in the spring of 1975. Simply titled Fleetwood Mac to reflect the reinvigorated band's renewed sense of purpose, it arrived in stores July 11, 1975 — and although sales started slowly, and never really took off in the group's native U.K., they toured behind it with a young band's dogged enthusiasm. "There were no limousines and Christine slept on top of the amps in the back of the truck," Nicks told Uncut. "We just played everywhere and we sold that record. We kicked that album in the ass."

That effort eventually paid off in spades. Fleetwood Mac's first single, the Christine McVie number "Warm Ways," failed to chart, but the follow-up — "Over My Head," also courtesy of McVie — peaked at No. 20 in the States, paving the way for the huge hits "Rhiannon" and "Say You Love Me" (both No. 11). In September 1976, over a year after its release, Fleetwood Mac topped the album charts, selling more than five million copies along the way.

For the group's longtime rhythm section, Fleetwood Mac's success was a sweet reward for years of grueling — and often futile-seeming — work. "John and I have been through some unbelievable moral/mental decisions," Fleetwood told Melody Maker. "But we never wanted to kick it. Perseverance and work kept Fleetwood Mac together and a lot of people before us gave up, sayin' 'This isn't worth it.'"

"We did interviews with Newsweek and People magazine recently," added McVie. "It's funny being on the same page next to a big article on Jimmy Carter. We're reaching audiences that never heard of Fleetwood Mac, and it's good to have finally gotten away from questions like, 'Whatever happened to Peter Green or Jeremy Spencer?'"

Of course, as Fleetwood conceded in his NME interview, that success came after another step away from the blues-influenced sound Fleetwood Mac started with. "We're certainly not sounding the same as we were eight years ago," he laughed, while hinting at the strong interpersonal dynamics that would come to shape — and occasionally overshadow — the band over the decades to follow.

"The band is very much more than just a band now," he mused. "There's a little story to be told with everyone who's in the band, you know. It's intriguing."

Fleetwood Mac Albums Ranked Worst to Best