The first bridge ever to be built of iron, in 1779, is perhaps the most important industrial monument in Britain. The bridge changed the pattern of communications in its area, and attracted thousands of sightseers. The first book with this title marked the bicentenary in 1979, explaining the conception, design, and construction of the bridge and its social impact. However, since then, so much new evidence has required a completely new account. Of the iron bridges built in the half century after 1781, this book identifies nearly twice as many as the first edition. The definitive history by the two authors best qualified to write it.