An exploration of the relationship between patterns of social interaction and social work practice which incorporates thirteen publications. The thread running throughout is the way in which new forms of social care practice are made possible by cross-boundary linkages. A 'Critical Review' sets the context and analyses the works. This is followed by the first published work which applies anthropological models to the study of social marginalisation. The second publication introduces the social network concept and investigates patterns of reciprocity and dependency in social care. The next section of the thesis consists of a 'commentary' on the Griffiths and Wagner Reports. This is followed by a closely related work arguing that there is a fundamental opposition between market and network models of social and community care. The thesis then looks at the ways the culture concept can be used to illuminate the cross-boundary practices associated with community care. The concept of culture and its relationship to cross-boundary working is developed more fully in the next section where it is argued that collaboration culture is paradoxical because it incorporates both respect for difference and a commitment to collective action and that resolving this paradox through collaborative work is a complex and skilled activity. The next section introduces a comparative dimension and suggests that studies of collaboration could be based on looking at the ways in which modern welfare systems try to solve the problem of potential fragmentation and lack of coherence. The work which follows on from this makes use of discourse analysis and network analysis to compare and contrast the rhetoric of partnership and collaboration with the way in which individuals think about their day-to-day cross-boundary work. This raises questions about the changing nature of working relationships in the field of social care and is followed by an investigation into the nature and effects of globalisation on social work in Europe. 'The Co-operation Concept in a Team of Swedish Social Workers' is an attempt to develop a cross-national framework for the analysis of community care focused on the cross-boundary networks of a team of hospital based social workers in Stockholm. The thesis then returns to somewhat broader concerns by means of a work which investigates the contribution of theories of social interaction to theories of social work. These concerns permeate the penultimate section on networking but in a more applied and specific way. The book which constitutes this section of the thesis argues that there is a distinctive theory of networking and that it can be applied to the whole range of social welfare and social care specialisms. The final work explores the impact of globalisation on the ways in which social workers currently experience their roles and develop their sense of professional identity.