As an internationally recognised disease classification, sudden infant death syndrome (SIDS) is unique in that the diagnosis is reached by exclusion, by failing to demonstrate an adequate cause of death. By definition it is imprecise, the diagnosis of SIDS depends on the thoroughness of the post mortem examination, the extent of detail given in the clinical history and the meticulous nature with which the death scene investigation is carried out. Even if these conditions are satisfied to some chosen specification, this is not an endpoint but a rather a beginning, as we are still left with the question of “why did these babies die?”

The tragedy of SIDS is not a modern phenomenon but was only christened a syndrome 40 years ago and, after extensive research, the possibility of finding a collection of symptoms and signs manifesting as a single cause appears extremely unlikely. Some experts suggest a triple risk causal mechanism for SIDS involving a vulnerable infant, a critical development period and an exogenous event that would not normally put a healthy child at risk. Other experts, frustrated with what they see as a definition of convenience, want to restrict the liberal use of such a diagnosis to exclude suspected cases of accidental suffocation and infanticide. Hypotheses continue to proliferate and, as the evidence for risk factors mount, the debate has widened from causation to the relative safety of accepted infant care practices.

In trying to understand how infants die, we have come to the realisation that we must first understand how infants survive. SIDS research has developed from basic epidemiological and pathological findings at death to a wider investigation of infant sleep structure, care practices, physiology, and genetics. This multidisciplinary approach is elegantly illustrated in Byard and Krous's book. The eclectic choice of contributing experts gives a clear insight into current thinking and recent discoveries in different fields, while challenging the reader with a subtle consensus of disagreement. The book gives detailed background of each debate but is more than a reference manual for other researchers in the field. Given the rarity of SIDS, many medical professionals may not have to deal directly with the sudden death of a child but will have to deal with mothers concerned about child safety, while some parents are reticent to accept advice unless they know how this has been derived, this book is also for them.

If there appears to be a lack of co-ordination in the approach among different research groups, a slightly over zealous interpretation of findings by some experts and perhaps more confusion than clarity in the overall picture, then this book has given a true reflection of SIDS research as it currently stands. There is no ending to the story because infants still die suddenly and unexpectedly, but if SIDS research is to be ultimately judged by the number of young lives so far saved then the endeavours of those involved should be highly commended.