It all began in this part of Pennsylvania, as Martha Capwell Fox describes in her book, “Geography, Geology, and Genius: How Coal and Canals Ignited the American Industrial Revolution.”

The book details the dramatic rise and fall of the coal, iron, slate and steel other industries that provided livelihoods and built these cities, Allentown, Bethlehem and Easton, and boroughs, among them, Northampton, Catasauqua, Nazareth, of the Lehigh Valley.

The Delaware and Lehigh National Corridor, which includes Bucks, Northampton, Lehigh, Carbon and Luzerne, counties provided the arteries of transport that fueled United States’ manufacturing power.

“People don’t realize how important this area was,” says Fox, a Catasauqua resident and archives coordinator of the National Canal Museum, Hugh Moore Park, Easton.

“Pennsylvania was the driver of the U.S. economy,” according to Fox.

“The Corridor led with easily-available mineral fuel, primarily coal, and metal production, mainly iron.

“Our region was the nation’s largest producer of pig iron, from 1840 to 1870; of cement, from 1880 to 1910; and of silk production, from 1913 to 1930.”

The region’s geography provided the Lehigh River and Delaware River, which supplied water for the Lehigh Canal and Delaware Canal on which boats transported the coal to market.

The geology provided slate, zinc and anthracite coal. Anthracite, with its high carbon content and low impurities, was in demand for iron production and was shipped to cities for heating.

The genius, says, Fox, was “a core of people who found a way to put all that together. They found a better way to do something.”

Biographical sketches in her book describe innovative businessmen who built industrial empires that have since disappeared.

These men, whose firms were often the main employers in the region, would build housing and in many cases provide a number of civic improvements. They were often close to their workers, taking a paternalistic, but autocratic, stance towards them.

“They were products of their time, which does not excuse them, but explains them,” says Fox.

The book’s many illustrations depict how the industrial landscape changed over the years. Nearly all the huge industrial complexes are gone or are no longer operational. Canal transportation, using intricate locks and large flat boats, was replaced by railroads. The elaborate infrastructure for mines and quarries is now mostly abandoned.

“Geography, Geology, and Genius” is also the story of immigrants.

“This country’s population wasn’t big enough to start the Industrial Revolution without them. They did the work no native-born American would do,” says Fox.

Silk has become a forgotten industry. Fox’s father ran Catoir Silk Company, Allentown, which was the last silk mill in the area whose only product was silk. It closed in 1989.

“At one time the silk industry had as many workers as the steel industry. It was the largest industrial employer of women,” says Fox. During its peak years, it was the only alternative women had to domestic service.

“There used to be 50 silk mills in Allentown alone. There was a speculative bubble in the 1920s. People invested who had no idea what they were doing. The company names would change many times in some of the locations.”

To make a list of all the area’s mills, Fox had to make trips to New York City over months. She needed to consult Davidson Silk Directories, which listed all the nation’s mills.

The book begins in the 1790s and although it concentrates on earlier times, it goes up to the present. Manufacturing is today the second biggest revenue producer in the Lehigh Valley after finance, insurance and real estate, even surpassing healthcare.

Manufacturing is not as noticeable now, since it has become so decentralized and not as dependent on huge plants.

“It is computerized now and uses smaller amounts of people,” says Fox, who gives an example of the cement industry, which is one of the few traditional industries that has not completely disappeared in the region.

“LaFarge Cement [in Whitehall] once had 200 people working in the quarry alone. Now it has only 120 people for the whole company, even though it is in operation around the clock.

“On a tour I took, there were only three people working the quarry remotely, in what looked like the control room of the Starship Enterprise.”

Fox’s 246-page book is illustrated with more than 200 photos, maps and historic drawings, including several rarely-seen color images. The book’s editor and designer is Ann Bartholomew. Publication of the book was supported by a grant from Furthermore, a program of the J.M. Kaplan Fund.

Says historian Frank Whelan, “This is the comprehensive history of the industrial development of the Lehigh Valley that local historians and lovers of local history have been waiting for. Well-written and profusely illustrated, it takes the reader on a journey from the charcoal-powered iron furnaces of the 18th century to the end of the glory days of Bethlehem Steel.”

“Geography, Geology, and Genius” is published by Canal History and Technology Press, an imprint of the Delaware & Lehigh Heritage Corridor. It can be purchased at the National Canal Museum, Sigal Museum, Lehigh Valley Heritage Museum and the Moravian Book Shop