Underpinning the works that comprise this PhD are four research questions that ask how people with learning disabilities might contribute new knowledge and understanding about theatre and alternative expressions of the world we share. Firstly, in what ways might the production of theatrical performance by people with learning disabilities contribute to a widening of the aesthetics of collaborative theatre making? Secondly, what kind of collaborations might emerge in this context and how might they produce alternative aesthetics? Thirdly, how can non disabled collaborators perceive and embody radically different expressions that may appear the result of pathology, defect, or feel unseemly and unaccountable within the context of normative systems and values? Finally, how might such expressions be understood as resonant and articulate within a crafted piece of work? The elements of this research, both practice and written publications contribute towards the development of an aesthetic that privileges the authorship of people with learning disabilities. This submission by the route of publication comprises three recordings documenting public performances, one recording that documents elements of the process involved in creating on of these performances, three articles and one book chapter, all published between 2009 and 2015. These works have emerged from my practice based research project that focuses on devising theatre with people with learning disabilities. The performance work is made by Cyrff Ystwyth, a dance-theatre company comprised of people with and without learning and physical disabilities. The methodology of my practice with Cyrff Ystwyth is to follow the lead of a person with learning disabilities and to support the production of a theatrical performance. This involves commitment to the ideas of the person leading the work, and reproduction, appropriation and learning of the physical and vocal material offered by the leader. I do not bring choreographic ideas or text to the work but instead depend on the presence of the leader for dramaturgical material. Cyrff Ystwyth work together every week for nine months of the year with our work culminating in a public performance.