In this paper, we theorize about Socio-Technical approaches to HCI. The Socio-Technical tradition indicates that looking at design only or mainly from a technical design side is insufficient to design systems for work and workers; instead the social and the technical need to be co-designed and contingent on characteristics of the context, the organisation, and its historical development. However, it also argued that this tradition does not provide enough handles for the design of interactive technologies for users. We present Socio-Technical HCI as a distinct field of knowledge outlining the Socio-Technical traditions where it is rooted, and illustrate these with three different conceptual frameworks that have been used to support the design, development, and evaluation of interactive systems. These frameworks are Cognitive Work Analysis, Human-Work Interaction Design, and Technological Frames. These frameworks are compared and analysed in terms of what are a balanced and comprehensive way to in address socio-technical, contextual, and design issues in HCI. It is argued why Human-Work Interaction Design is best placed to address these issues.