This thesis provides a critical history of the origins of Critical Systems Thinking (CST). Its theoretical framework is based upon a detailed analysis of the work of the French philosopher Michel Foucault. It is aimed at demystifying CST's claims of pursuing some "neutral" human interests, while arguing that CST's origins are grounded on managerial interests and practices. After providing a comprehensive review of Foucault's ideas, it examines the main approaches found in the history of the management sciences. It shows how each new management approach made its contribution by producing a new type of worker according to changing historical circumstances; a worker that is increasingly supposed to freely and democratically pursue his/her own interests, which "coincidentally" follow those of the management. It also discusses how different strands of systems thinking, such as OR and soft systems, were produced to support these managerial paradigms. Finally, it examines the role that current managerial techniques, as exemplified by TQM, have played in the production of CST in the 1980s. In this context, it argues that CST's role in modern organisations is to contribute to the refinement of current managerial techniques. CST's discourse is portrayed, thus, as contributing to the masking of the micro-techniques of normalisation present in contemporary organisations.