Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.The Clean Tech Revolution: The Next Big Growth and Investment Opportunity, is a 2007 book by Ron Pernick and Clint Wilder, who argue that commercializing clean technologies is a profitable enterprise that is moving steadily into mainstream business. As the world economy faces challenges from energy price spikes, resource shortages, global environmental problems, and security threats, clean technologies are seen to be the next engine of economic growth. Pernick and Wilder highlight eight major clean technology sectors: solar power, wind power, biofuels, green buildings, personal transportation, the smart grid, mobile applications (such as portable fuel cells), and water filtration. Very large corporations such as GE, Toyota and Sharp, and investment firms such as Goldman Sachs are making multi-billion dollar investments in clean technology.