The book presents an integrative theory of hard-to-maintain behaviours, that includes hard-to-reduce or eliminate behaviours like smoking and other drug use, overconsumption of food or unsafe sex, and hard-to-sustain behaviours like exercise and sun-safe behaviours. Most of the examples come from the author's work on tobacco smoking, but it is relevant to anyone who is concerned to understand why some forms of desirable behaviour are so hard to achieve, and to those trying to help people change. It also has important implications for public health campaigns and for the development of policies to nudge behaviour in desirable ways. The book provides readers with frameworks to: - Determine whether a "hard to maintain" behaviour is a result of the skills needed to perform it, its reinforcement history, the way the person thinks about it, the context, or some combination of these. - Better integrate cognitive and behavioural change strategies, including emergent strategies related to mindfulness and acceptance, plus novel ways of retraining operational processes. - Understand the different nature of challenges for behaviours where multiple attempts are typically required before the desired behaviour pattern is sustained. - Better understand the role of feelings and emotions as influences on behaviour. - Understand the limits of environmental factors to determine change. - Understand the limits of self-control and will-power.