An excellent work marred by a little too much enthusiasm, this book will convey to the student of history the notion that the middle ages were not the black hole of lack of technology that most historians portray them to be. The author compares the changes in technology, and the scope of their results, to the Industrial Revolution of the nineteenth century, and he may be pushing the analogy a bit. However, it is certainly true that technology did advance in ways in the Middle Ages. As for biases and tone, the author veers deceptively about, now seeming anti-industrialist, now communist, now capitalist, now labor historian. The book is marred by a final chapter in which the author tries to draw a parallel between the Middle Ages and the modern day that is both not well described and does not seem to be accurate given the circumstances of the world 20 years after the writing. But for the descriptions of technology alone, and of corporate-like structures in the middle ages, this is a good read.