This thesis uses the work of Michel Foucault to analyse the three main knowledges around sex at work - scientific modernism, liberal feminist sexual harassment knowledge and re-eroticization knowledge. The main argument is that such knowledges can be identified as generating subjectifying power effects; that is to say. this thesis argues that modern human subjects are produced through the operations of prevailing power/ knowledge regimes such as those around sex at work. It is further suggested that the subject positions which these knowledges generate can, in line with Foucault's argument that 'everything is dangerous', be identified to have particular implications. A program of semi-structured interviews has been completed in a university and in a financial services company in order to assess how powerful each knowledge around sex at work has been with regard to subjects in the respondent group. Resistances to the knowledges were also catalogued. Acknowledgement is also made where appropriate of power effects of and resistances to these knowledges with regard to subjects in the wider social. Importantly, analysis is also offered of the implications of the subject positions identified; that is to say, of what it might mean for these men and women to understand themselves in these ways. This thesis therefore conforms to Foucault's recommendation that intellectual work should be used to subvert claims to truth and to reveal the effects of power so that subjects may begin the 'critical ontology' of themselves. This project of self rests on an awareness on the part of individual subjects that what that they know of themselves is nothing more, and nothing less, than the power effects of particular knowledges. Foucault suggests that this kind of relationship with self allows for a certain degree of self-fashioning - that we can come to be able to choose the ways in which we know ourselves. The concluding part of the thesis addresses the criticisms that have been made of this vision of a new form of subjectivity and, in so doing, clarifies the ethicopolitical contribution of the kind of Foucauldian analysis that has been attempted here.