Preface The energy scenario@ of which transport is but one sector@ is shaped by political and economic factors@ such as energy security and local environmental concerns@ and global issues@ such as climate change. World demand for energy in general@ and for transport in particular@ is increasing rapidly. Moreover@ the increase in demand for transport energy is expected to be skewed heavily toward commercial transport. The internal combustion (IC) engine@ fueled mostly by petroleum-derived liquid fuels@ has been the main source of transport power over the past century and is likely to remain so in the foreseeable future@ though alternatives such as electrification of the transport system will play a role. However@ engines are changing@ primarily driven by the need to be more efficient. They will also have to meet increasingly stringent emissions standards@ be affordable@ and satisfy customer demands such as driveability in a globally competitive market. Fuels will continue to evolve to minimize local and global environmental impact in their manufacture and in their use in engines. Conventional fossil fuels will constitute most automotive fuels in the foreseeable future@ but they will have to change to adapt to changes in engine technology. Unconventional transport fuels such as biofuels@ gas-to- liquid (GTL) fuels@ compressed natural gas (CNG) and liquefied petroleum gas (LPG) will also have a role to play. Hydrogen might become a viable transport fuel if it overcomes significant barriers in production@ transport@ storage@ and safety. Also@ the fuel cells that require hydrogen must become viable. This book considers these issues briefly in Chapter 1@ and Chapter 2 introduces practical transport fuels. Chapter 3 discusses an important practical topic about a fuel effect on engines that is not usually considered in text books?? deposits in engines. However@ the primary focus of the book comprises the implications of IC engine development trends for future fuels. In particular@ the autoignition behavior of practical fuels provides the unifying thread to help understand how these changes might influence future fuels. An attempt is made to bring together fundamental studies in autoignition such as ignition delay measurements in shock tubes and experimental studies in IC engines.