Sandhu, who calls himself a particularist, was born in West London but grew up in a small town called Gloucester, near the Welsh border. He collects greasy-spoon menus and plans to take a road trip to Poland because he heard the population may diminish by 17 percent over the next few decades, a curiosity he wants to see for himself. For his next book, he intends to explore how the Singer sewing machine changed the world, an interest fueled by the East End, where, starting in the 1880s, the sweatshop system employed poor immigrants who worked in their cramped homes for the tailored-garment industries. The book will also serve as a vehicle to explore the history of his parents, who worked in the garment industry but never wanted to talk about the experience.

When he sees evidence of the East End's past on our walk, it quickens his pace. He ­delights in old signs that carry outdated phone numbers and wrong prefixes. He talks about light pollution and the politics of light (how urban hipsters move into dodgy areas for the feel of living on the edge but then complain about the lack of street lights).

When we enter a street that extends beyond the hoots of horns and traffic and the shouts of ambling youth, he stops to consume the silence. "You get these pockets of silence, which are both alluring and magical for me," he says, looking up to the sky. "I want to find the stars. I want to find the moon. I want to find the silence in the city, because normally it's blaring and jarring."

We walk past council flats, and Sandhu speaks about the countless workers who reside behind the netting curtains and who likely sew on buttons for 25 pence an hour. Those workers, the ones toiling just beyond the darkness while the city sleeps, stay with Sandhu after he writes an episode. He ­remembers the immigrants who keep the gleaming metropolis running and who act as a kind of informal radar system to the mainstream city as they clean the office spaces and ferry merrymakers home and tend to the city's sewers. "I've been struck by how many people, no matter how badly paid or onerous their jobs, no matter how grim their living conditions, are still alive to beauty and to enchantment," he says, remembering cleaners in London's docklands who showed him their cell-phone photos of dawn over the Thames.