The Continuity Hypothesis of dreaming states that waking life is continuous with dreams (e. g. Schredl and Hoffman, 2003), but the ways in which it has been defined lack coherence and agreement (e. g. Domhoff, 2011; Hobson and Schredl, 2011), and many of the factors postulated to influence the continuity of waking life into dreams (e. g. Schredl, 2002a) have rarely been studied. The present thesis addressed these issues by researching the meaning of `continuity', the ways in which waking life is continued into dreams, the factors that influence continuity, and the implications the findings have on the potential function(s) of continuity. Because of the disparate perspectives on continuity, the thesis approached the empirical investigation of it from a broad, inclusive perspective, and utilised a diverse range of methodologies. Two theoretical chapters (a literature review and a methodological review) and five empirical chapters are presented, as well as one final chapter to bring the findings together in relation to continuity function. A dream diary study, an interview study, a questionnaire study, a longitudinal case study, and a systematic-awakenings study were all conducted in the pursuit of the research aims. Continuity was found to be influenced by the type of waking-life experience, emotionality but not stressfulness, individual differences, the time gap between the waking-life experience and dreaming, and time of night; it was also found that an individual's experience with continuity may be considered a type of trait of dreaming. The findings were interpreted in light of a number of functional theories and nonfunctional theories of continuity, most prominently an emotional memory assimilation theory. The thesis also contributed novel methodologies for the study of continuity, including the development of the Continuity Questionnaire and a systematic method of conducting and analysing interviews.