Jonathan Trott's book begins in a toilet. Not for him the glamorous surroundings of sun-streaked cricket grounds or open-top buses, instead the symbolic confinement of the smallest room. Unguarded is about how he got there, and how he found his way out. His first page, set after his penultimate Test innings, a three-ball nought in Barbados, is unsparing. As he stares in the bathroom mirror he notes his lined face and chipped teeth: "My hair had gone, and somewhere along the way, the fun had too. Batting had become torture."

As with KP: The Autobiography, published by Kevin Pietersen on his exit from international cricket, Trott's account is a state-of-mind book. The exhaustion and frustration are fresh on the page. While this adds a certain urgency, I think it's a book that Trott will look back on as a snapshot rather than a truly reflective and rounded vision of who he was and what he accomplished.

It is far better than Pietersen's book, which circled around the same subjects like a tongue on a rough tooth, to the point that it became unreadable, but that circularity of thinking is here. Trott's preoccupations are with how he's perceived, whether that is by his fellow players, by commentators and pundits or by the wider world. Perhaps George Dobell, his excellent collaborator, sensed as much. The decision to include some fairly long contributions gathered from Kevin Pietersen, Alastair Cook, Andrew Strauss and Andy Flower serve the dual purpose of mitigating Trott's insularity and providing the reassurance that he is not just respected by his peers but held in great affection as a person too. He is a friend to everyone on that divided list.

This is a book with the adroit structure of memoir, told in the voice of autobiography. The chapters are thematic, each set in a particular place and time, so we zig-zag from Barbados to Brisbane, touching down in the Cape Town of his childhood and The Oval of his triumphant first Test.

There comes a moment when the physical skills dip and decline and the emotional energy required to withstand the challenge changes and deepens, and you no longer feel young and indomitable; anxiety seeps like water through a ceiling

Dobell deftly sketches the cricket-obsessed kid with some warm vignettes; the young Trott and his father playing on adjacent pitches, leaning on their bats and smiling at one another; his driven mother laying into his bowling at a school parents v pupils match; the sports shop he grew up in, which left him unable to bear an untidy grip on a bat handle - as a Test player he goes through his team-mates' bags and adjusts them while they're not looking. It darkens as Trott is sent to a sports psychologist when he reacts violently to his first run of bad scores, and by the time of his Test debut, capped by an Ashes century, he is entirely defining himself by the game he plays: "It was everything I had ever wanted, and everything I dreamed it would be."

England, with Trott as their rock-solid, iron-hard No. 3, climb the mountain to world No. 1. It's a high that lasts until the final of the Champions Trophy in 2013, when the disappointment of that game induces his precipitous fall.

Fear is an unexamined, sometimes unacknowledged, subject in cricket and other sports, maybe because to do so implies a lack of courage. That is daft, not least because courage doesn't really exist without fear. But its manifestation in cricket drives at the heart of Trott's book. The professional batsman trains incessantly to resist and repel very fast, short-pitched bowling. They are not afraid of the ball in the same way that a boxer is not afraid of being punched. But like a boxer, damage accumulates, through a fight, through a career, through all of the unseen hours of sparring and training. There comes a moment when the physical skills dip and decline and the emotional energy required to withstand the challenge changes and deepens, and they no longer feel young and indomitable; instead anxiety seeps like water through a ceiling.

In Trott and in many batsmen it begins as a kind of impugning of their masculinity. "I felt I was being questioned as a man," he writes. "I felt my dignity was being stripped away with every short ball I ducked or parried. It was degrading."

Trott is confronted by a truly fearsome opponent exactly as he arrives at this moment in his life. Mitchell Johnson hits him on the head with a bouncer during the ODI in Edgbaston in 2013 and the trickle of anxiety becomes a flood. He breaks down on the field before the next game in Southampton and Ashley Giles has to pull him out with a "back spasm", an excuse that reinforces Trott's perception that his anxiety is somehow shameful or weak. By the time the contest is transplanted to Brisbane, he is a sitting duck, his technique wrecked by an early movement across the stumps, his concentration disrupted by a headache, the anxiety manifesting now as a desire to crash his opponent out of the attack: "normal circumstances have left town… I want to hit it. I want to smash it. I want to prove I can play this stuff."

Johnson is the wrecking ball not just for Trott but for the storied team that is falling apart around him: Graeme Swann's elbow has gone, Matt Prior is struggling, Kevin Pietersen too; and their coach, Andy Flower, is responding in the only way he knows, by pushing everyone harder. Trott's account of the disintegration is urgent and moving, his voice and Pietersen's harmonising on what went wrong (a minor theme of Unguarded is how clear and true Pietersen's vision of England was - and it is expressed far better and more concisely here than in Pietersen's own book).

Trott's insecurities are deep in the bones of Unguarded. At the times of his greatest anxieties you want to stop reading, put an arm around him and tell him it's all going to be okay. As well as the journey in and out of a toilet, he begins a less steady one from a life and a personality defined by being a cricketer to the more rounded years beyond. I hope that he knows he takes many admirers with him, and this raw, sometimes visceral account of a modern sportsman's life will surely bring him more.

Unguarded: My Autobiography
By Jonathan Trott
Sphere, 2016
288 pages, £20

Jon Hotten blogs here. @theoldbatsman