What makes the modern world work? The answer to this deceptively simple question lies in four "grand transitions" of civilization--in populations, agriculture, energy, and economics--which have transformed the way we live. Now a fifth transition is underway: the environmental changes that will determine the success or eventual failure of the preceding transitions that have made the world we inhabit today.

Vaclav Smil is Distinguished Professor Emeritus at the University of Manitoba. The author of more than 50 books, he conducts interdisciplinary research in energy, environmental and population change, food production and nutrition, technical innovation, risk assessment, and public policy. He has worked globally as a consultant and frequently delivers invited talks at conferences and workshops throughout the world.