This thesis describes a qualitative enquiry into the experiences of families visiting an adult intensive care unit (ICU) during a critical illness of a family member and nurses’ perceptions of families in this environment. A Grounded Theory approach was taken. Nine families (12 adults, 12 young people) with a family member in intensive care and twenty intensive care nurses in five focus groups contributed their experiences to the study through group interviews. Families described the admission of a family member as a traumatic event. The core experiences of families which emerged in the study revolved around uncertainty. Drawing on Davis’ (1963/1991, 1966) concepts of ‘clinical uncertainty’ and ‘functional uncertainty’ a number of strategies families and young people developed in dealing with the situation were identified. ‘Clinical uncertainty’ captures the unknown and unknowable aspects of critical illness. The ‘Functional uncertainty’ category emerged later in the research process and brings to light management of information disclosure for functional gain as a communication strategy. Functional uncertainty was identified in communications between nurses and families and between parents and children within families. Moreover, young people used the same ‘functional uncertainty’ strategy when disclosing information to peers within the school environment. ‘Keeping normality in life’ and ‘fishing for information’ and the associated strategies were identified as direct responses of young people to clinical and functional uncertainty. The strategies identified provide new insights into how young people process a critical illness event in their families. This emphasises the importance of listening to young people’s voices and the need to include young people in future studies. ‘Nursing in public’ emerged as an overarching theme within the data from nurses’ interviews. The contrasting interests of nurses and families in the context of critical illness became evident when open visiting policies were discussed. The promotion by policy makers and nursing scholars of a patient centred health care service and thus the implicit integration of families into care challenges nurses to adapt their working practices. Whilst this study provides evidence for the importance of integrating families into care it also shows the needs of nurses are in danger of being marginalised. Respecting the needs of families and nurses the question becomes how best to balance the competing needs of both groups. It is suggested that a ‘partnership in care’ approach which is firmly based on negotiations between nurses and families under the leadership of nurses will allow for the emergence of family care in intensive care, to the benefit of patients, families and nurses.