London is not a big city. By global standards, it's a fairly calm, quiet, orderly place of medium size that functions pretty well most days. In fact, compared to bigger cities like Guangzhou, China and Dhaka, Bangladesh—places you likely never think about—London feels a little suburban by today's yardstick.

You can't help but realize this as you read The Victorian City, Judith Flanders' chronicle of London's rise as a grinding, sweat-stained, runaway-horse of a metropolis in the 19^th century. Subtitled “Everyday Life in Dickens' London,” The Victorian City positions itself as a story about the past. The truth is, it couldn't be a better reference point for the booming urban age we're careening through today.

By “we,” I don't mean city-dwelling Westerners. Much as we'd like to think that bike lanes and Brooklynization are the most important developments of 21st century metropolitan life, Western cities hardly register on today's scale of urban transformation. The crucial narrative today is unspooling in the street markets of Kuala Lumpur and Nairobi, the unregulated transit networks of Santiago, the ad-hoc garbage collection systems of Kolkata, and the gray-market pipelines that buoy the economies of Accra and Phnom Penh. These are the cities that will define the urban world in the coming decades. They also happen to be growing and functioning much the way London did in the 1800s.

Though Flanders never makes this link explicitly, she must be aware of it—her descriptions of London back then are almost perfect depictions of urban life in today's developing world. “The streets were a place to go to, not to go through,” she writes of the city's bustling open-air markets. She describes a period of relentless civic construction—vast new roads and transit systems, and new congestion to go with them. She alludes to jobs like street sweeping and garbage collecting being done by informal workers rather than the government. And the multitudes: “No matter where [a man] goes... he cannot get beyond the crowd,” she quotes a visitor from Philadelphia complaining in 1852.

Compare this imagery with today's rapidly urbanizing regions—the forces that drove London forward 150 years ago are similar to the ones that propel many developing-world cities today. Publicly funded construction is goosing the economies of cities like Chengdu and Istanbul. Informal workers make up over half the workforce in much of urban African. Street vendors crowd the sidewalks of Bangkok and Lima.

These parallels are important because they can help us predict the future. Assuming climate change doesn't destroy them first, developing-world cities might look something like present-day London a century from now. We've gotten so used to the idea that glassy towers and grandiose waterfront promenades are the marks of a so-called world-class city that we often forget how these places started out: messy and smelly and loud. Scrappy. Poor. What looks like filthy chaos at the moment is actually the kinetic energy that gives birth to modern metropolises.

It worked for London and New York in the 19^th century. Hell, it worked for Tokyo in the 20^th—after that city was decimated by Allied bombers, it was basically one big slum. As urbanists Matias Echanove and Rahul Srivastava write in Next City, the Tokyo government was too preoccupied with restoring basic services to regulate anything, so residents simply rebuilt their businesses and neighborhoods themselves. “What those residents built was, essentially, an enormous unplanned settlement—a settlement that, in some respects, was built much the same way that Dharavi, the huge unplanned settlement in Mumbai, is being developed today.” In other words, Tokyo's post-war shantytowns, unpaved streets and rubble-strewn gardens grew into what is now widely considered the most modern, technologically advanced city in the world.

In cities, what looks messy and chaotic is often the seed of innovation—the ramshackle beta versions of many modern urban amenities were reared in muddy old London. There was the neighborhood greenmarket, observed grimly by Dickens in Martin Chuzzlewit as “rows and rows of old women, sitting on inverted baskets, shelling peas.” There were taxis, called “hackneys,” which were rickety stagecoaches cast off by the rich and repurposed as transport for hire. (A more upscale version, the cabriolet, or “cab,” was later imported from France). Even the long-haul buses whose drivers received kickbacks from the taverns where they stopped for meals were pioneering a charade recognizable to anyone who's ridden the New York-to-Boston Chinatown bus, which stops at the same Burger King every time.

Some of London's more ridiculous ideas never made it out of the 1800s, and these failures make up some of the most entertaining parts of the book. Did you know that London at one point surfaced its streets with cast iron, and even wood? Or that, lacking alarm clocks, people hired watchmen to come to their house in the morning and pound on the door to wake them up? Some of the norms that guided urban life were exactly the opposite of today's. There were, for instance, no rules about which side of the street to drive a vehicle on, yet, as one Londoner reported of his daily walk to work, pedestrians walked in perfectly straight lines “so orderly that,” on his three-mile commute, “I could, by keeping to the right, read my paper the whole way.”

The sad part is that today, the authorities of a city so unrestrained would likely crack down on its unregulated markets and transit systems, just as governments from Jakarta to Sao Paulo are doing right now. These cities want to be the next London, and when they look at that city, they see order and formality. But trying to impose such order by chasing away informal commerce and culture is myopic. The lesson of Victorian London is that modernity isn't built one luxury high-rise at a time. It's cultivated through the daily activities of people, over the course of years, warts and all.