Ultrarunner Ken Posner Explores Ego, Endurance, and the Catskill Mountains in Chasing the Grid

Kenneth Posner has a habit of walking away. From Wall Street, where he spent years parsing mortgage markets; from family dinners, even on Christmas Day, when the mountains called; from the steady rhythms of ordinary athletic life, where marathons might have sufficed. He is perpetually stepping off the train, as he likes to say, borrowing a metaphor from Winston Churchill’s Boer War escape. For Posner, the tracks of conventional life are never enough.

His new book, Chasing the Grid: An Ultrarunner’s Physical and Spiritual Journey in Pursuit of the Ultimate Mountain Challenge (VeloPress), chronicles his completion of the Catskill Grid—climbing each of the 35 Catskill High Peaks in every month of the year. That’s 420 summits, a feat that makes most peak-bagging look like a Sunday stroll. Written in the same obsessive cadence as the climbs themselves, the book toggles between the raw detail of ultramarathon suffering (blackened toenails, zombie death marches, nettle stings) and the lofty meditations of a man in search of transcendence.

But it’s Posner’s contradictions that animate the story. The Gardiner resident frames the Grid as a path to quiet the ego, to “let the mountains be your teachers.” Yet he is also a record-holder who relishes recounting the time strangers passing him on the trail called him a “hill-climbing ninja.” He writes about minimalism—going barefoot, shedding gear, learning to read lichen and moss as trail markers—but he meticulously tallies peaks, times, and injuries. The Grid is offered as an escape from the “quiet desperation” Thoreau warned against, but it’s also a ladder of distinction, a way to stand apart.

When I spoke with Posner, he did not shy from these tensions. “Accomplishments matter,” he told me, “as long as you don’t turn into a raging asshole about them.” His definition of transcendence, he explained, is less about erasing achievement than about blunting the “internal Lady Macbeth” that constantly urges more. On a descent from the top of Sugar Loaf, he recalls coming face-to-face with his ego while sitting under a ledge in the rain. “I realized it had become quiet because my ego wasn’t chattering at me to be better than everybody else,” he says.

Effort itself is Posner’s lodestar. For him, the Grid was less about conquest than calibration: “We’re puny creatures with limited willpower,” he said, “but the energy is all there in the universe. The question is how you manage yourself, the small adjustments you make along the way.” To illustrate, he cites a 1950s documentary about the !Kung, hunter-gatherers of the Kalahari Desert who chased a giraffe for days across the veld before bringing it down. To Posner, that is the ur-ultramarathon: not spectacle, but survival. “This is normal,” he says. “Sitting all day in a cubicle is not.”

And yet, for a man so attuned to the natural rhythms of endurance, the unnatural intrudes. He is still a corporate executive, toggling between investor conferences and Catskill summits. Posner writes about lichen and owls as if they are companions, but also about the dopamine hit of checking peaks off a list. He insists he is not exceptional, just another person seeking connection, but his life is built on doing what 99 out of 100 would never attempt.

What redeems the contradiction is his candor. Asked why he not only climbs but writes about it, Posner shrugs toward his past as an English major. Writing, he says, is how he crystallizes experience, how he makes sense of what the mountains are teaching him. Early drafts of Chasing the Grid were unreadable, he says with a laugh—420 stream-of-consciousness chapters written without using the word “I.” Only later did he relent and place himself, squarely, in the narrative. Ego, it turns out, is hard to erase even on the page.

The Catskills themselves are the book’s co-protagonist. For Posner, the mountains called him away from spreadsheets and city streets into a realm of nettles, bears, and mossy ledges. “They challenged me to strip down,” he says. “Not as a high-tech operator, but as a person.” He quotes Zen masters on the “walking green mountains,” invokes John Burroughs on the virtues of the naked foot, and aligns himself with Thoreau’s insistence on daily doses of nature. If the prose veers at times toward the mystical, it is tethered by a runner’s blunt pragmatism: The need to keep moving forward, even in pain.

The Christmas hike still nags at me. Most of us would never leave the warmth of family on a holiday to chase a cold summit. Posner admits as much. “Sometimes you have to make a radical move,” he says. For him, that move led to the Grid. For readers, the book offers not a prescription but a provocation: What train are you on, and when will you jump?

In the end, Chasing the Grid is less about negating ego than about negotiating it. Posner is equal parts analyst and ascetic, record-chaser and barefoot mystic. The contradictions don’t cancel each other—they power the story forward. If the book convinces you of anything, it’s that the path worth following is rarely a straight one.