This thesis summarises a selection of forty-two studies [1-42], published by the author during the period 2000-2012, investigating the conceptual basis of Insomnia Disorder, and its evaluation and treatment, principally using cognitive and behavioural interventions. The work reflects a range of research methodologies including experimental, psychometric, qualitative and population-based studies, and randomised controlled trials. Important theoretical contributions to the literature published in this period are also included and reference is made to major textbooks, position papers, and
influential chapter contribution