The scientific community can almost unanimously agree that a method must be found to substitute in lower carbon energy sources while diminishing reliance on traditional fossil fuels. However, no clear solution yet exists that could facilitate such a shift on either a national or international level. Discussions on the subject have thus far revolved around finding economically feasible energy solutions in the short term, and fail to place long-term evidence in adequate perspective. Such evidence exists though, in case studies of different nations gradually shifting from fossil fuels to low-carbon energy solutions. These shifts have taken place over many decades, and are important to take into account for all future low-carbon energy debates. This book closely examines four of these long-term cases that have occurred since the global oil crisis of 1973: Brazil's shift to biofuels, Denmark's implementation of wind power, French nuclear power, and Icelandic geothermic energy. These case studies inform Dr. Araujo's thesis that a significant nationwide shift to low-carbon energy sources can occur in under fifteen years, and that technological complexity is not necessarily a major impediment to these shifts. Specific to this project alone, Dr. Araujo has completed nearly five years of research, and has interviewed over 120 different scientists, government workers, and academics. The book is written both for professionals in the environmental science and policy-making communities, as well as graduate or undergraduate students studying energy sustainability. Included in each chapter are relevant technology briefings, allowing the non-scientific reader to understand enough the science behind the book's material.