The book provides an overview of the Slow Onset Disasters (SLOD) in the urban built environment discussing potential strategies to assess and mitigate multiple climate change related risks. Climate change evidence has been reported in the last decades, suggesting that the anthropogenic activities are accelerating these changes towards a warmer and more polluted environment. In this context, SLODs have been linked to climate change related disasters and have been stated to have a higher impact risk within dense built environment (BE). Therefore, the book presents a description of the most relevant SLODs, their significance, and confluence, the way in which scientists and entities are monitoring their progression at different scales, a structured risk assessment strategy and the deconstruction of the BE characteristics that make it more prone to SLODs risk. In addition, it highlights the necessity of adapting the traditional risk assessment methods, to account for different vulnerabilitytypes, including the morphology and materiality of the BE, and the BE users characteristics. In fact, individual features influence users responses and tolerance to environmental stressors, because of age, health, gender, habits, and behaviour, thus impacting the users vulnerability. Exposure can then amplify these issues, since it defines the number of users that can be effectively affected by the SLOD. Starting from this perspective, the book first traces literature-based correlations between individual features, use behaviour, and individual response to the SLOD-altered open spaces. Then, a novel methodology, to quantify the variations of users vulnerability and exposure, is offered, to support designers in quickly defining input scenarios for risk assessment and mitigation. Lastly, it demonstrates, through a case study, the SLOD risk assessment framework proposed and the evaluation of the efficacy of risk mitigation strategies.