"This brings me to a central feature of my concept of parenting - the provision by both parents of a secure base from which a child or an adolescent can make sorties into the outside world and to which he can return knowing for sure that he will be welcomed when he gets there, nourished physically and emotionally, comforted if distressed, reassured if frightened. In essence this role is one of being available, ready to respond when called up on to encourage and perhaps assist, but to intervene actively only when clearly necessary. In these respects it is a role similar to that of the officer commanding a military based from which an expeditionary force sets out and to which it can retreat, should it meet with a setback. Much of the time the role of the base is a waiting one but it is non the less vital for that. For it is only when the officer commanding the expeditionary force is confident his base is secure that he dare press forward and take risks.
In the case of children and adolescents we see them, as they get older, venturing steadily further from base and for increasing spans of time. The more confident they are that their base is secure and, moreover, ready if called upon to respond, the more they take it for granted. yet should one or other parent become ill or die, the immense significance of the base to the emotional equilibrium of the child or adolescent or young adult is at one apparent."
- John Bowlby, A Secure Base: Clinical Applications of Attachment Theory