As far as weird trips go, the story of The Beach Boys ranks as one of the weirdest in the well-frazzled history of rock’n’roll. Initially, it all seemed so simple: gentle, talented Brian Wilson corralled his two brothers Dennis and Carl, plus his cousin Mike Love and a neighbour, Al Jardine, into a group. They meshed sweet, complex harmonies with the elemental rumble of early rock’n’roll, added lyrics that were paeans to the idyllic surf-cars-and-girls lifestyle of young, white, middle-class California, and – easy, easy – made some of the most blindingly great singles of all time.

Only The Beatles rivalled their popularity. But there were problems. The Boys manager — the Wilsons’ father, Murry — was a bullying, jealous failed songwriter who habitually interfered with the music, humiliated his sons and made appalling business decisions. And Brian’s gentleness was increasingly revealed as emotional fragility. After several horrendous panic attacks, he stopped touring, experimented with hallucinogens and bedded down in the studio to work on ever-more ambitious music.

In 1966, he completed Pet Sounds, an album that still sounds so unbelievably lovely that the NME voted it the best album ever in 1993. The sheer scope of the music — intricate, dramatic and with an innate melancholy that perfectly complements the lyrics of fading innocence — set a new benchmark for rock’n’roll. It made anything seem possible. In response, The Beatles made Sgt Pepper, the concept album was thus invented and pretension was introduced to a new generation.

Meanwhile, Brian was taking entire orchestra wearing fireman’s helmets, then blamed the alchemic power of the music for starting a number of blazes in LA that same night. The other Beach Boys — especially the frequently thuggish and philistine lead singer, Mike Love — were baffled by, and hated, the freaky new music, haranguing Parks over his impenetrable lyrics.

“I think Smile was absolutely stellar for its time; it stretched the envelope. We were pushing the industry to do things,” remembers Van Dyke Parks. “And Brian was the most courageous, innovative personality I’ve ever met in the recording studio. Bar none. He showed valour, it was like I was with a great warrior. When I was interested in being a great lover, he showed me, at that early age, that he was interested in being a great warrior. He brought me into a New Age Of Man. He did something very fraternal for me. It was… an important relationship for me. And I would like to think that courage is contagious.”

Courage and genius notwithstanding, Brian Wilson suffered a terrifying psychological collapse that caused him to spend much of the next 20 years cowering in his bed, a bloated and traumatised casualty. The other Beach Boys — including wild brother Dennis, by now consorting with Charles Manson — took musical control, with Brian contributing fewer and fewer songs, still occasionally brilliant, but often simpler and unmistakably disturbed.

Periodically, throughout the ‘70s, a Brian Wilson comeback campaign would be launched, only to be stymied by increasingly duff albums and his horribly erratic mental state. One psychologist — a former music business hustler called Dr Eugene Landy — made some impression in the middle of the decade, but was dismissed by the band and Brian’s then-wife Marilyn for outrageous salary demands and for dictating every single detail of his patient’s life.

So The Beach Boys turned into a cabaret act. Mike Love, hooked on transcendental meditation, took cynical control of the band. Dennis, wasted, died in a diving accident and Brian’s state deteriorated until, in 1983, Landy was called back on to the job. For the best part of a decade, he cleaned Brian off street drugs, slimmed him down and helped him to record two solo albums (one, eponymously titled, was released in 1988; the second, Sweet Insanity, was shelved by the record company two years later). He also completely took over Brian’s life.

Shortly before work began on that first album, Sire Records boss Seymour Stein appointed an experienced Boston producer and musician, Andy Paley, to look after the project. Paley — an obsessive Beach Boys fan, one-time Patti Smith Group member, Madonna sideman and Boys Wonder/Plastic Bertrand producer — immediately befriended Wilson, but discovered that Landy’s influence had strayed way out of the treatment room and into the studio.

“I think they probably saved his life,” says Paley, “but just because you’re able to get someone off drugs or save someone’s life doesn’t make you a songwriter or a record producer.”

The solo album — overproduced, but still Brian’s best effort by far since the early ‘70s — was released and acclaimed. Brian appeared healthier, but rumours persisted that Landy’s manipulation of him was increasing, suggesting he bullied him into writing songs at ridiculous speed and then pronounced the resulting doggerel to be genius. Paley had little to do with Sweet Insanity — an album that reportedly contains duets with Paula Abdul and Bob Dylan, and features Brian rapping — and is clearly not heartbroken that Sire refused to release it.

“The state of California held a conservancy trial,” explains Paley, “which is when they appoint a conservator to someone who needs help managing their own affairs. This is what happens when someone is perceived by good friends of the person in question as an evil, or bad, influence. Relatives can get together — in this case it was Carl and Brian’s daughters and Brian’s mother — and say: ‘This guy’s gotta go.’ They had a conservancy hearing and trial and a new conservator was appointed and this guy was told to get lost.

“Things immediately took a turn for the better. Brian started having a life of his own. He wasn’t allowed to have girlfriends before that — I mean, it was really rough. All those people were moved out of Brian’s life by the State Of California. By law.

“And the day, the very day, these people moved out of Brian’s house, Brian called me and he said: ‘Now I can do whatever I want. Come on over, let’s write songs, let’s have some fun.’ He was so happy to be free.”

It was around this time — late 1992 — that Van Dyke Parks reappeared on the scene, pursuing an erratic, idiosyncratic solo career with vague plans to make an album about the “quintessentially Californian experience”, and with the idea to have Brian Wilson singing on it, especially on one song — Orange Crate Art.

“I had waited 30 years and I thought that was an appropriate, a polite, amount of time,” he says, wryly.” I took it out to him one night in torrential rain, frightened to death to play it to him, because of his reputation for high standards in music. He’s got two assistants in the room with him [men employed by the State Of California after Landy had been dismissed] watching my every move, because they thought that I might give Brian some smack, uppers or downers or something, I guess. As far as I was concerned, the walls were melting, I was so petrified.”

Brian, though, liked the song and agreed to sing on it. They went into the studio, with Parks gradually introducing more new songs, writing and producing everything and using Brian’s multi-tracked voice as backgrounds, claiming he would add his own voice, as the lead, later.”

“I continued to record the back-up voices, and then one day Brian said: ‘Whose record is this?’ I said: ‘Well, it’s our record, Brian.’ We’re maybe four tunes in and he’s starting to get that sinking sensation that I’m tricking him into doing work. Every time we started a new song, he kept insisting that I start singing. I told him: ‘Quite frankly, Brian, I can’t stand the sound of my own voice and I’d like to be able to listen to this.’ He said: ‘I don’t blame you.’ I was conning Brian Wilson into doing this, no two ways about it, I was conning him.

Brian, of course, ended up singing everything. The resulting album, Orange Crate Art (due for release in early November), is a curiosity; ostensibly a mellow, crafted Parks record, with celestial Brian Wilson vocals. A little cheesy in places — it’s much closer in spirit to composers like George Gershwin than to anything so vulgar as rock’n’roll — it still makes for a fine showcase for that startling, soaring voice. Now that the project’s completed, plans are afoot for the two of them to record an album of standards next year.