"Ideas are funny things. Invisible and weightless, they have no material substance, yet they have the power to change the course of history. Or as the french writer Victor Hugo put it: "One can resist invading armies: one cannot resist an invasion of ideas."  

~Time Magazine~

100 Ideas 

That Changed The World

"The 100 we (Time Magazine) settled upon stood out to us in part because taken together they demonstrate the many different things an idea can be. Those would include centuries-in-the-making developments like the alphabet and codified law; schools of thought like stoicism and existentialism; cultural watersheds that took place on many fronts, like humanism and romanticism; individual intellectual breakthroughs like thos of Descartes or Darwin; and crucial inventions like photography and computers. And while the ideas under discussion in this book are not the only ones that shaped the course of human affairs, we're confident they rank among the most important."

http://www.time.com/time/magazine