Life is short and the Grand Canyon is long, especially when you paddle your way down it in a kayak. From the put-in at Lees Ferry, not far below Glen Canyon Dam, the Colorado River winds 226 miles between walls of primordial rock to a take-out at Diamond Creek, on the Hualapai Indian Reservation, dropping through dozens of major rapids along the way.

Beyond that is slightly more river, more canyon, but the urgency, the majestic ferocity, and the sense of otherworldly containment dissipate down there, as the canyon walls tilt back into rubble slopes of Sonorant desert vegetation and the water's awesome momentum dribbles out anticlimactically into flat, inert Lake Mead.The deep magic and adamantine power that make this particular canyon grander than all others on Earth lie in those upper 226 miles, between the launch point and Diamond Creek. My own little kayak, of stiff yellow plastic, is nine foot two.

Simple arithmetic tells me that I'll need to travel 130,271 boat-lengths from start to finish. It's a ratio conducive to humility.

On water like this, each boat-length of headway involves two paddle strokes and, through the more serious rapids, maybe a quick tactical brace to prevent being flipped upside down. The lovely thing about a whitewater kayak is that, far beyond any other sort of water craft, it offers maneuverability in exchange for vulnerability, a tradeoff that intensifies the boater's sense of intimate interaction with a river. Climbing into a snugly fitted kayak, wedging your butt between the hip pads, arching your knees up into the thigh braces, is more like buckling on skis than like boarding a vessel. This is a sporting tool, not just a mode of conveyance. Stability is achieved, not given. a whitewater kayak even differs drastically from a sea kayak--roughly to the degree, say, that riding a unicycle in the circus differs from pedaling a ten-speed across Nebraska. Offering so little inherent equilibrium, so many dimensions of surpr...