The success of this book stems from its clear and concise, yet detailed summary of the advances in seismic source studies during the past two decades. Dr Kennett presents a mainly theoretical account of the passage of seismic waves from source to receiver, linking the theoretical development to the nature of seismograms observed across a wide range of distance scales - from a few kilometres, as in shallow reflection work for geophysical prospecting, to many thousands of kilometres for earthquakes. A unified framework is presented for all classes of seismic phenomena, for both body waves and surface waves. Each topic is taken up systematically, including many topics not normally covered in discussion of propagator theory, such as source representation theory, generalised ray theory, and the calculation of complete theoretical seismograms including all wave effects arising from the presence of the Earth's surface.