There has been a great need for a text such as this for some time now, with the last general book on sudden infant death syndrome (SIDS) published over a decade and a half ago, in 2001. Since that time many significant developments have occurred in our understanding of sudden and unexplained deaths in pediatrics, ranging from updated definitions with increased emphasis on mandatory death scene investigations to highquality scientific work examining the role of neurotransmitter abnormalities in the brain. The issue of sudden death in toddlers over a year of age (SUDC) has also become an area of study, with a clearer understanding of the usefulness of the more general term sudden and unexpected death in infancy (SUDI). The Triple Risk Model has stood the test of time and has facilitated the integration of laboratory-based work with epidemiological risk factors. Many fringe theories have fortunately finally fallen into well-deserved historical obscurity along with odd entities such as status thymicolymphaticus.

As the reader will quickly realise, the text is an extremely eclectic mix of chapters written by experts in their respective fields. Important chapters deal with the history of SIDS, the role of parent organizations in promoting bereavement support, the very raw issue of parental grief, and research into the underlying mechanisms associated with SUDI. The later chapters focus variably on processes and locations, particularly within the brain, the roles of which in SUDI are being more clearly teased out and understood.

Of necessity there is some repetition in chapters, as SIDS and SUDI in general are a heterogeneous mix of mechanisms and processes that cannot be boxed into discrete areas. While this has sometimes led to different authors taking somewhat contradictory positions on certain subjects, it merely reflects the complexity and reality of the SIDS/SUDI arena today.

The editors hope that this text will have enabled experts from a variety of backgrounds to explain and elaborate on their particular areas of study and investigation. It will also serve as a summary of SIDS, SUDI, and SUDC as we know them today, and will lay the foundation for further exciting discoveries. As such, hopefully this book will provide an invaluable resource for individuals across many arenas, including parents, clinicians, medical examiners, and researchers. We are very close to understanding why SIDS/ SUDI occurs: our next challenge is to prevent these tragic deaths from ever happening.