(Henniger (1999) included Bowlby's in the list of theories essential to a successful early childhood programme.) John Bowlby argued that it is vital that the child attaches to a single prime caregiver (the mother) and that failure to attach or incorrect separation from the mother poses grave risks to the child's future psychological development. Children deprived of mother love were potential criminals. For mothers, fathers and early childhood educators this created questions and fears about whether a child was attaching sufficiently, how moments of material separation should be handled and when. In Bowlby's words: