ntroduction This presentation will illustrate how activity theory as a theoretical framework,facilitated an indepth understanding of the ICU patient discharge process.Emerged in the 1920s and 1940s,activity theory was developed in the Russian cultural—historical school of psychology (Engestrom,1987; Engestrom,Miettinen,& Punamaki,2006; Vygotsky,1978).The current activity theory,consists of two interacting activity triangles (Figure 1),has been used around the world in the past two decades to study cognitive work systems in a variety of settings,such as computer—supported learning (Barab,Schatz,& Scheckler,2004; Zurita & Nussbaum,2007),group work analysis in education (Choi & Kang,2009),and analysing medical practice (Engestrom,2000).In large organisations,many local activity systems are interconne