This covering statement introduces the nine published outputs in this submission, and explains their genesis. It considers the implications of the growing visibility of the sexual orientation strand for individuals and organisations operating in the UK context before and after the introduction of the Employment Equality (Sexual Orientation) Regulations 2003 (hereafter the Regulations). The PhD advanced knowledge and understanding of the following: the rationale for and drivers of sexual orientation equality work in UK trade union, public, private and voluntary sector organisations over the last two decades; the equality/diversity structures, policies and practices introduced by organisations in order to become more inclusive of lesbian gay and bisexual (LGB) people; LGB people’s perceptions and experiences of these sexual orientation equality and diversity policies and practices; LGB people’s voice, activism and agency in influencing the changes which have been taking place. The covering document provides details of the research projects and the interpretivist case study methodology on which the published outputs draw. It summarises and links the aims and principal findings of each output demonstrating that they form a coherent body of work. It concludes that although the introduction of the Regulations has been a positive trigger to sexual orientation equality work in the UK, progress remains uneven within and across organisations. Thus, it identifies voice mechanisms such as LGBT trade union and company network groups as key tools for inclusion. The conclusion locates the PhD as an original contribution to the advancement of sexual orientation organisation equality/diversity research. It does so by discussing its empirical and theoretical contributions to a sexual orientation research agenda which has been developing in waves subject to social, political and legal change and mobilisation in LGBT communities in different parts of the world.