"Successive stages of development occurred at different times with the various human tribes... We may safely assume that fundamental discoveries and inventions, such as the wheel and the utilization of fire, were made in a number of places and periods, and many times all over again."
- from A History of Invention by Egon Larsen
"The greatest invention of the nineteenth century was the invention of the method of invention... One element in the new method is just the discovery of how to set about bridging the gap between the scientific ideas, and the ultimate product. It is a process of disciplined attack upon one diffculty after another."
- from Science and the Modern World by Alfred North Whitehead
"A distinctive feature of the 20th century was that the inventive process became powerfully institutionalized... and proceeded in increasingly close proximity to organized research. Three clusters of innovation dominated American technology in the 20th century: the internal combustion engine, chemistry, and electricity and electronics. Realization of the economic consequences of these technological advances has typically required considerable refinement and improvement of the crude early versions of the products that incorporate them."
- from Paths of Innovation by David Mowery & Nathan Rosenberg