I checked my balance and peered apprehensively at the sheer drop below. Once I felt comfortable, I radioed down to Stu.

'I'm just gonna unclip quickly,' I said.

My walkie-talkie crackled straight away. Stu sounded pretty stressed. 'Dude, keep the rope on!'

I edged forward, my hands and feet scoping out the summit for any loose rock. The ridge pinnacle was still only a meter wide, if that, but I felt pretty stable.

'This bit's fine,' I said. 'The rope makes it harder for me...'

Danny MacAskill lives on the edge.

The cyclist is legendary for his YouTube viral videos like The Ridge, Cascadia and Imaginate: nerve-racking montages of stunts which scale everything from mountain peaks, rooftops, ghost towns and movie sets. His life is one of thrills, bloody spills and millions of online hits.

It hasn't been an easy ride. Doubt, stress and the 'what if?' factor circle every trailblazing trick, which require imagination, fearlessness, groundbreaking techniques and an eye for a good camera angle. He has spent his life pushing the extremes; somehow, he's still around to tell the tale.

In this unflinching memoir of mayhem, Danny shares his anarchic childhood on the Isle of Skye and early days as a street trials rider, takes us behind the scenes of his training and videos, shares never-seen-before sketches from his personal notebook, and reveals what it takes to go the next level - both mentally and physically.

Join Danny for a nerve-shredding ride. Just be sure to bring a crash helmet.