Runners in the Boston Marathon. (Tim Bradbury/ Getty Images)

Joanna Scutts is a fellow at the Center for Women’s History at the New York Historical Society, and the author of the forthcoming “The Extra Woman: How Marjorie Hillis Led a Generation of Women to Live Alone and Like It.”

Early in the morning, after finishing Vybarr Cregan-Reid’s hard-to-cat­egorize “Footnotes,” I am penned in a corral with more than 5,000 other runners in New York’s Central Park, as the sun heats up, music pumps and officials congratulate us through loudspeakers for supporting the charity of the day. This four-mile race, with its entry fee, timing chips, bib numbers, medals and tightly managed course, is far removed from the solitary, unencumbered, mostly barefoot running that Cregan-Reid celebrates: a plastic bottle of Gatorade to his handful of water gulped from a mountain stream. I do my best to relax into a restorative state of “soft fascination,” which the author describes as “a sort of meandering, free-form mode of thought inculcated most successfully by natural environments,” absorbing the light splintering through the leaves and a wave of scent from the flowering trees overhead. I listen to my breathing and the ambient noise of the park rather than blocking them out with headphones. Throughout the run, I’m absorbed by the large questions this book raises about what I’m doing here. Is this natural? Healthy? Good for me? If so, how, exactly — and why?

A literature professor at the University of Kent in southern England, Cregan-Reid isn’t an obvious guide to the science of the human body in motion, but he gamely engages experts in neuroscience, psychology, paleontology and evolutionary biology in a quest to confirm what he already feels to be true: that running outside confers powerful physical and mental benefits. One expert in running biomechanics describes in awed terms the complexity of the human foot and advocates running without shoes, while another group of researchers is exploring the benefits of immersing ourselves in green environments — the “room temperature of our visual spectrum” — for benefits that are easy to feel but hard to measure. Runners or not, readers have no doubt encountered the thread of worry that links all these areas of study: that humans are struggling with a fundamental maladjustment to modern life and that sitting all day indoors, hunched over our screens, is making us sick and miserable. Running offers one form of escape from modernity; in essence it is “analogue,” “hunter-gatherer,” even “Palaeo.”

Cregan-Reid is no dispassionate scientist, however; his quest for understanding is rooted in his own emotional and creative relationship with running. In this, the book invites comparison to novelist Haruki Murakami’s 2008 book, “What I Talk About When I Talk About Running,” the preeminent title in the highly specialized sub-genre of memoirs connecting physical and literary endurance. Murakami is a self-punishing runner, given to feats of bloody-minded stamina; Cregan-Reid by contrast is amusingly hapless, constantly going out in the wrong gear, getting lost or caught in the rain, forgetting to eat, and never bringing water. An asthmatic who relies on medication, he admits to plenty of procrastination and avoidance of exercise. Writing a book about running turns what was once a respite into homework and eventually forces him to reclaim it by “bunking off” — playing hooky from an academic conference on Thomas Hardy to take to the streets of Dorchester. There’s no disciplined trade-off here between a daily 10K and a daily thousand words — instead, running is a matter of meanderings and trespasses, over mountain paths in the rain and through gaps in fences, past “keep out” signs on the grounds of private property. He runs through the streets of Brighton and the chalk hills of the nearby South Downs; along the banks of the Charles River and among California redwoods; in inevitable Lake District rain; and eventually, in the London Marathon. He runs at first to outpace a creeping depression and then to escape a failing relationship, and learns to brush off the stares and comments of passers-by as he runs barefoot over the grass and concrete of south London.

“Footnotes: How Running Makes Us Human,” by Vybarr Cregan-Reid (St. Martin's Press/St. Martin's Press)

The author’s enthusiasm for the uncharted path inspires fascinating forays into English literary history, where Samuel Taylor Coleridge, Virginia Woolf, John Ruskin and William Hazlitt, among others, offer insights into the relationship between the body and the natural environment. One run takes Cregan-Reid along the Cornish coast near the remote village where Thomas Hardy met his wife and where, after an “overwhelmingly unhappy” 40-year marriage, he returned in his imagination to memorialize her in poetry. Hardy was a walker, not a runner, but his “immersive” attention to the details of the natural world nevertheless parallels the “frictive immediacy” of running and the way it forces unusual attention to the details of the earth, air and environment.

The vital interplay of humans and nature is not to be confused with utilitarian “exercise” — especially not on a treadmill. Focusing on the brutal imprisonment of Oscar Wilde, Cregan-Reid explores the gym staple’s origins in the penal system of late Victorian England, where it was deployed as an instrument of physical and psychological torture. What this author talks about when he talks about running is freedom, not fitness — and his idealistic vision touches only briefly on the fact that not every runner is as free as a young white man to run without fear, harassment or threat.

If anything here inspires a gym-bound or sedentary reader to venture outside and claim that freedom all the same, it is less likely to be the book’s science than its art. The runner’s heightened attention is conveyed in the writer’s intensified prose, especially when describing sensory phenomena such as the “mineral tang” of rain on concrete — a smell called petrichor, from the Greek word for stone and for ichor, “the golden fluid that runs in the veins of the gods and the immortals.” In the tradition of the English nature poets he writes about, as well as of contemporary “psychogeographers” who seek playful new ways to explore urban environments, Cregan-Reid ventures out most often into undramatic, everyday landscapes. Under the right sort of sustained attention, these ordinary places can nevertheless burst into revelation — call it a runner’s high, Woolf’s “moment of being” or some other flash of insight. Whatever it is, it’s worth chasing.

How Running Makes Us Human

By Vybarr Cregan-Reid

St. Martin’s.
334 pp. $26.99