Unexpected deaths in infancy: how understanding of causes and prevention has developed over 100 years

As Archives of Disease in Childhood approaches its 100th anniversary, we describe in this article how the understanding of the aetiology, epidemiology, parent-infant interactions and approaches to prevention of unexpected deaths in infancy has evolved over the century.We have been involved in research into unexpected infant deaths, support of bereaved families and prevention of such deaths since 1976 (PF), 1992 (PB) and 2006 (AP).