Macfarlane begins the book with a brief overview of writers who wrote about walking and a short listing of different types of paths around the world and throughout history. He mentions that some paths, such as those in Ireland left over from the Famine, were created by people who had no choice but to walk, and who ultimately found nothing at the end of their path except death and loss.
After the massive slaughter of British men in World War I and the resulting death of the civilian population from the Spanish flu, there was a renewed interest in 1920's and 1930's Britain in walking the old ways (p. 21). Walking the roads of the past were a way to connect with people and events from the past. The liminal quality of the path, which existed to connect two places and was not of these places, gave it the ability to connect its walkers with other times.
The author himself has had experiences on paths where he has felt close to the past. At one time he had explored the sunken "holloways" of Dorset with Roger Deakin, paths so worn into the soil by time and use that they could be twenty feet below the surface of the land:
"In the dusk of the holloways, these pasts felt excitingly alive and coexistent - as if time had somehow pleated back on itself, bringing discontinuous moments into contact, and creating historical correspondences that survived as a territorial imperative to concealment and escape.
Two years after that visit, Roger died young and unexpectedly. Four years after his death I returned to Dorset to re-walk the same holloways and found myself tracking our own earlier traces...and experiencing startingly clear memory-glimpses of Roger himself, seen at the turn of a corner or ahead of me on the path." (p. 22-23).
My own first exposure to the British belief in the ability of paths to contain past events is one that is familiar to anyone who has read the books of Susan Cooper. In her book The Dark is Rising the child hero, Will Stanton, spends much of the book wandering around the snow-covered landscape of his small English town just around the winter solstice. His local old way, known irreverantly as "Tramps Alley" but truly called "Oldway Lane" saves his life by calling on the power it has stored through its use for centuries by people fighting against the dark. Will is able to move between the present and the past when he walks Oldway Lane albeit in a more concrete fashion (since he is a fictional character) than that of Robert Macfarlane.
Rudyard Kipling also explores the ability of a path to move between time in his poem "The Way through the Woods" from Rewards and Fairies. The poem comes just before "The Marklake Witches" story in the book. The story is a supposedly true historical tale told to Dan and Una, the two main characters based on Kiping's own children, by a teenage girl who had died of consumption over a hundred years earlier. The girl, named Philadelphia, loved to ride and appeared to the children dressed in a riding habit. Just as Puck gives her the ability to move forward in time to talk to the children, the overgrown woodland path contains the sounds of Philadelphia's rides out on her horse.