The aim of the present thesis was three-fold. The first aim was to critically review the applicability of the current models of insomnia to late-life insomnia in light of existing research. The second aim was to create a model specifically for older adults whilst accounting for the limitations in previous conceptualisations in definitional criteria and often-contradictory research findings. The final aim was to empirically test the model for its utility in addressing the problems associated with late-life insomnia. As a result of the literature reviews on the sleep of older adults and current models of insomnia, the Cognitive Consolidation Model was created and tested. Seven studies were conducted with older adults to examine the existence and importance of specific components of the Cognitive Consolidation Model and their interrelationships. The results from the studies support the models tenet, in that late-life insomnia progresses in a cyclical fashion through the consolidation between night time worry over sleep performance and daytime anxiety over the consequences of poor sleep. Additionally, the role of sleep hygiene in late-life insomnia was made questionable. Furthermore, it was shown, through longitudinal changes in some components of the model, that the psychological aspects of late-life insomnia are not fixed but evolve over the course of the disorder, exerting differential influence at different time points. Moreover, two pivotal aspects of the consolidation process in late-life insomnia were outlined and tested, namely the existence of sleep discrepancies and daytime sleep catastrophizing. Furthermore, the cognitive processes underwhich sleep catastrophizing occurs were examined. The thesis finishes with a discussion of the limitations within the current research agenda and possible avenues to address these problems whilst further advancing an understanding of late-life insomnia. Treatment options and extensions to the Cognitive Consolidation Model are also advanced.