Singer-songwriter Paul Simon and actress Carrie Fisher’s attraction to each other flared quickly — only to combust. Their explosive relationship stemmed from their swinging states of depression, Fisher’s drug use and an array of personal insecurities, according to Homeward Bound: The Life of Paul Simon by Peter Ames Carlin.

The biography, out Oct. 11, explains that it was this mix of love and personal crises that caused Simon and Fisher to marry, divorce in 1984 and continue to date on and off for about a decade before finally ending their relationship after a psychedelic trip in the Amazon.

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Fisher died Tuesday after suffering a massive heart attack on an international flight four days earlier.

“They fought a lot,” writes Carlin. He describes a scene in which they yelled at each other, and stopped just as abruptly because they were “laughing too hard to snarl anymore.”

According to the book, Fisher was already heavily involved with drugs (she was introduced to them when she was 13) when she first was introduced to Simon while filming Star Wars. Though she was being pursued by three other men, her attraction to Simon was instantaneous. “Once they saw each other, no one else mattered to either of them,” Carlin writes. They quickly moved into an apartment in New York City’s Central Park West together.

“Carrie added velocity to [Paul’s] life, a kind of wild energy that often set him alight and sometimes made him scream,” continues Carlin. But Fisher’s highs also came with very intense lows.

Image zoom Paul Simon and Carrie Fisher (Credit: Ron Galella/WireImage)

“[Paul] didn’t want to have to deal with Carrie when she came pin balling home with Christ only knew what powders and pills sizzling inside her feverish skull,” says Carlin. “Then it would be her turn to crash back to earth, ashamed of her wild moods and indulgences, suddenly convinced she had neither the brains nor the maturity to keep up with her older genius boyfriend.”

Carlin describes how Simon’s dislike of Fisher’s drug use, their busy schedules and Fisher’s crazy habits (like her “extravagant, drug-fueled vacation to Switzerland”), resulted in talks of breaking up.

“But then they thought again. Breaking up would be too sad,” writes Carlin. Instead, they decided to get married, which was “such a happy prospect they fell in love all over again.”

The couple got married in Simon’s apartment and they continued to celebrate while he was on tour. According to Homeward Bound, Fisher acted with him as he hosted episodes of Lorne Michaels’ comedy series, The New Show. This joyous start didn’t last, explains Carlin. The newlyweds had to return to reality where “the same problems were waiting just where they had left them.” After less than a year, they divorced.

Image zoom Homeward Bound: The Life of Paul Simon

But, just like a Star Wars revival, their story wasn’t over. A few months after the divorce they went from talking to each other, to dating, to living with each other again, Carlin explains.

“There had always been something perfect about them when they were getting along: the way they huddled together, the way he grounded her, the way she could make him laugh so easily,” Carlin says of their renewed romance. “And he loved her, with a desperation that could frighten him.”

But Carlin also adds that this passion wasn’t enough to fix their personal problems. Though Fisher went to rehab in the mid-1980’s, she still suffered from severe manic-depression. In the book, it’s detailed how Simon went to therapy because of his own unhappiness.

“[Carrie’s] depths were unimaginably deep, and Paul’s were nothing to sneeze at either,” writes Carlin. “So they clung to each other with a passion that could both soothe and abrade.”

Seeking happiness, Simon and Fisher visited a brujo (a spiritual healer) in the Amazon where Simon was recording an album. Under a shroud of darkness, Carlin writes that the brujo sang as the couple drank a special tea made from the leaves of a psychedelic plant and caapi vine — a recipe designed to cleanse their spirits. While Simon rested his head in Fisher’s lap, she said she had a vision.

She described “feeling pinned beneath Paul’s ever-spinning, ever-controlling brain; about the way he, like so many powerful men she knew, assumed his expertise and control over every situation,” writes Carlin. After this revelation, they left Brazil and Fisher left Simon for good.

While Simon and Fisher were over romantically, they weren’t quite finished. Carlin explains that during their almost 12 years together, Fisher helped raise Simon’s son, Harper (the child from his first marriage to Peggy Harper). Simon’s first born shared his depression, as well as the usual insecurities faced by the children of superstars. According to Homeward Bound, Harper self-medicated with alcohol, marijuana and LSD as a teenager. By the time he had turned twenty-one, he had turned to more serious substances: heroin, morphine, amphetamines, and Demerol. Fortunately for Harper and those who loved him, he later got help “and family order was restored.”

In a way, it had. By then, Simon was remarried and would go on to have three more children. Despite this domestic setup, there’s no denying what was once between Fisher and Simon.