The late 19th century was a period of explosive technological creativity, but arguably the most important invention of all was Thomas Edison's incandescent light bulb. Unveiled in his Menlo Park, New Jersey, laboratory in 1879, the light bulb overwhelmed the American public with the sense of the birth of a new age. More than any other invention, the electric light marked the arrival of modernity.

The light bulb became a catalyst for the nation's transformation from a rural to an urban-dominated culture. City streetlights defined zones between rich and poor, and the electrical grid sharpened the line between town and country. "Bright lights" meant "big city". Like moths to a flame, millions of Americans migrated to urban centers in these decades, leaving behind the shadow of candle and kerosene lamp in favor of the exciting brilliance of the urban streetscape.

The Age of Edison places the story of Edison's invention in the context of a technological revolution that transformed America and Europe in these decades. Edison and his fellow inventors emerged from a culture shaped by broad public education, a lively popular press that took an interest in science and technology, and an American patent system that encouraged innovation and democratized the benefits of invention. And in the end, as Freeberg shows, Edison's greatest invention was not any single technology, but rather his reinvention of the process itself. At Menlo Park he gathered the combination of capital, scientific training, and engineering skill that would evolve into the modern research and development laboratory. His revolutionary electrical grid not only broke the stronghold of gas companies, but also ushered in an era when strong, clear light could become accessible to everyone.