How do stars – or any of us – tick? Artists, of course, have bodies of work for their exegetes to parse, and Lou Reed’s is one of the more influential in western popular music. From his early days in the Velvet Underground documenting the New York demi-monde to a series of dissonant and beautiful solo works thereafter, the public Reed had a reputation as a curmudgeon who did not suffer fools gladly.

But he had another body of work: his actual body, damaged by drug use and beleaguered by diabetes and hepatitis C. That body was a work in progress, transformed by the practice of martial arts.

“It saved him,” notes Princeton creative writing professor AM Homes, who Lou Reed consulted when he set out to write a book about tai chi in 2009. It’s a sentiment echoed by many others in this version of that book – finished posthumously, scrapbook-style, by artist Laurie Anderson, his partner, in collaboration with Reed’s close associates Stephan Berwick, Bob Currie and Scott Richman.

Here, then, is a wealth of oral history-style interviews with a wide array of Reed’s contemporaries conducted by Anderson and the book’s other editors, and transcripts where Reed discusses his tai chi practice with martial arts magazines. The guest list is both star-studded and intimate, from Iggy Pop to Anohni, via producers Tony Visconti and the late Hal Willner, director Darren Aronofsky, the late photographer Mick Rock, magician Penn Jillette (the former president of the Velvet Underground fan club and hoarder of bootlegs) and many of Reed’s closest friends. His transplant surgeon is consulted; classical pianist Hsia-Jung Chang is one of the relatively scarce female voices in this martial arts crowd.

According to many, Reed was really a sensitive, traumatised guy given to great acts of generosity; a soul utterly transformed by taking up tai chi in the 1980s. It is a demanding pursuit, spiritually minded. Reed became reliable – and relentlessly productive. Various people might have introduced Reed to martial arts. The prize probably goes to his ex-wife, Sylvia. But Reed had grown up on kung fu movies: the ground was already fertile. And as a denizen of the good old, bad old New York, Reed also had a keen interest in physically defending himself.

As serious as Reed was about his music, he was just as intense about the Chen style of tai chi – a fighting art, rather than a gentle form practised by elderly people in Chinese parks. He practised daily, often on his roof, having become an avid student of a Chinese tai chi master called Ren GuangYi. “Some people race cars,” Reed shrugged to an interviewer. He, on the other hand, wanted to tame his anger. Reed was particularly fascinated by the interplay of alert serenity and explosive power Ren embodied.

So obsessed with tai chi was Reed – recounts one long-suffering tour manager – that he used to travel with a collection of fighting swords. Fellow hotel guests used to regularly call security when they saw an armed man in the grounds or practising near the lifts late at night. “It can be an addiction too,” muses fellow artist-cum-martial artist Ramuntcho Matta.

Tai chi seeped into everything – not least Reed’s music. In the 00s, Reed took Ren on tour with him too, accompanying the master’s movements with music to often baffled write-ups. A technique known as claw hands had an impact on Reed’s guitar playing style. His 2007 LP, Hudson River Wind Meditations, was an attempt not just to accompany tai chi practices, but to somehow distil their essence into sound.

It was fun too. Reed renamed one tai chi move “delivering the pizza”, the better to teach it to neophytes whom he would help coach at Ren’s classes. At the point of Reed’s death – after a liver transplant, in 2013 – Anderson confirms that he was practising a form called cloud hands.

Reed fans with a grasp of martial arts probably have most to gain from reading this extensively illustrated doorstop of a book, one that can, to the uninitiated, appear to get bogged down in detail. Another narrative gradually emerges. Editor Scott Richman points out that Reed was worried that Ren would return to China if he didn’t earn enough money, so publicising his master’s work became another of Reed’s obsessions. Hence the 2010 Ren DVD Power and Serenity, soundtracked by Reed’s music, directed by Richman – and the tours, and the book.

But the musical perspectives are many. Jonathan Richman recounts being adopted by the Velvet Underground as a youngster, then crushingly rebuffed for years by Reed. Iggy Pop is reliably warm and witty on his own parallel healing process via yoga, qigong and sea bathing. Anohni, formerly of Antony and the Johnsons, is a particularly insightful witness to Reed’s kindness and inner tumult. In her introduction, Anderson expresses the ambition to produce a “multifaceted portrait” of Reed, as a seeker of grace, control and peace of mind. She has.

• The Art of the Straight Line: My Tai Chi is published by Faber (£30). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply