Does progress always require that mistakes be made along the way? If so, how can or should progress be approached when the mistakes could be potentially fatal or catastrophic?

This book is a revision of a book written ten years earlier. What advancements or achievements would you include if you were to revise the text today?

Some of the devices depicted in the book have since become obsolete (manual typewriters, the record player, the VCR). Some, such as the plow, were included, even though archaic, because they are still used in some form. Do you think there is still something to be learned from studying machines which are no longer in our everyday lives? How important will it be to understand the combustion engine, for example, if it ever becomes obsolete?

Sensors and detectors are discussed starting on page 290. Written before September 11th, 2001, when...