We stood out on deck, flinching in the wind, as the ferry headed up the Lynn Canal, Juneau Harbour fading in the wake. Ice-capped massifs towered over us, dense forests rolled down to the shore and a large pod of orcas breached port side. Alaska can make you feel quite small. Fiona and I had come to climb Mount Fairweather. Don't feel abashed if you haven't heard of it. Having been spotted and inappropriately named by Captain James Cook back in 1778, this 4660-metre peak on Alaska's west coast has since then generally been swaddled in cloud. We were only there because it happened to be on my list.

When police claimed to have found a hit list in Radovan Krejcir's home, sceptics suggested it was planted: surely a ruthless criminal wouldn't need to write down the four names he planned to bump off. But to me it rang true. For in my experience, every man has a list to tick off. After all, that's what gives our lives purpose. Having collected the seven continental summits and three poles, plus all the James Bond videos, my life was drifting aimlessly, till a friend directed me to a website listing prominent peaks, alluringly titled the 'World's Finest Fifty'.

The concept of prominence is rather like black hole theory: just when you think you've got it, it slips away from you, especially when you're trying to explain it. Essentially, a peak's prominence is calculated by taking the highest point on the planet (Everest) and then, assuming you were able to traverse over whatever terrain lies in between, measuring how far you'd have to climb up again. Island high points are easy enough, with their prominence matching their elevation above sea level. But for all others, it's a more complicated task, requiring you to locate the key saddle separating them from their parent. Fortunately, the authors of the website had performed all these calculations, leaving me just to find the peaks in my atlas. Then again, for some that was tricky enough.