Life is an adventure, and whether you approve of it or not, most of us need risk to feel alive. It should therefore be no surprise that a mountaineer, upon reaching the top of a white-knuckle climb, feels a surge of elation, a joy for life. The heightened sense is not just a result of having earned a fine view through exercise, though that surely contributes. It is also because life has suddenly gained intensity from flirting with the stark alternative. While moving on rock, the climber had no thought for anything but the next handhold, the flow of movement, the 'now'. With the climb over, the relief at having succeeded (and survived), floods back. "It's great to be alive!" I was once driving through Switzerland with some friends. We stopped for lunch at the base of a small crag that sloped like a wedge of gray cheese beside the road. With a couple of days up our sleeves, we were in no rush to reach Genoa, so after eating and lying in the sun, we put on our climbing boots for some bouldering. I soon found myself traversing solo along a horizontal line that started halfway up the wedge. At an area of increasing difficulty, I made a long step up only to find the handhold smaller than I expected and sloping downwards. Back climbing was out of the question. Ahead, the line vanished. I looked down and cursed my own stupidity. I was forty feet above a jumble of boulders, my boots, hooked onto a half-inch wide ledge, were starting to pump like a sewing machine. My fingers screamed to let go. Eight feet above me, a piton protruded from a wall of smooth rock. I marveled that anyone could have put it there. It was my only hope. Releasing one hand from the wall, I slipped out of two tape slings and joined them with a cats-paw. I dangled the double sling and touched it against the wall to steady it, then I swung. The top of the sling snuggled neatly over that piton on the first throw. Gently I tested it with my weight, then scrambled up to safety. I flopped thankfully onto roughly horizontal ground and stared into the heart of a small white alpine flower, acutely aware of its life and my own, and the connection between us. The emotional rearrangement from that experience has lasted thirty years. At the time I barely mentioned it to my companions from embarrassment. The piton was luck, but hooking it first swing was not. Something inside my brain had cleared the way for one intense, precise calculation and everything worked. Although it was a stupid and embarrassing situation to be in, it was also one of the finest moments of my life. I survived! The risk in this case was a bad one but it was real and so were the benefits. I would never knowingly put myself into that situation again and I rank it alongside a time when I narrowly missed a head-on collision or another when I just avoided being mugged in a wild Central American city. In each case I found that as well as learning practical lessons in survival, colors seemed brighter, birdsong more noticeable, trees greener, and my companions more important to me. The problem, of course, is that if we go through life pumped up with too many of those situations, it is statistically improbable that we will live beyond our teens. Enter the concept of 'good risk'. What I call 'good risk' is risk where the odds are in keeping with the expected rewards and where you can maintain reasonable control over the process. It won't necessarily supply the life-altering results of a brush with death, but it does provide a tune-up and, besides, most of us can do without going eyeball to eyeball with the grim reaper. Combine this rush with the natural beauty of the wild, and you have the ingredients for the 'outdoor adventure experience'. Climbing, back-country skiing, mountain-biking, kayaking, canoeing, hang-gliding, diving, caving, and yes, bungie-jumping all provide the opportunity for this tune-up. But, you say, these can be seriously dangerous things to be doing. …