Why has the energetics of organometallic species become an area of recognized importance? What methods are available to obtain information on reaction enthalpies and bond `strengths'? What other methods are likely to be used in the future? Is the present thermochemical data bank satisfactory for our needs? How accurately can we estimate the energetics of organometallic reactions? Can theory offer reliable help? Which are the main problems to be tackled by the experimentalist? These are some of the questions addressed in the present book, which contains contributions by most of the leading groups in the area of organometallic thermochemistry.