This volume collects theoretical reflections, methodological contributions, and case studies relating to military, modern, and industrial heritage, which represent specialist fields of research for which the debate on recognition, protection, and, consequently, the potential for reuse is still open to investigation and further scientific inquiry. Selected papers show that processes of knowledge, interpretation, and conservation across the three areas largely employ the same principles, methodologies, and operational practices. In addition, the problems that have hindered and continue to slow down their protection and reintroduction into the useful life cycle through sustainable reuse operations, whether adaptive or otherwise, are also similar. If military and industrial heritage suffer from being the product of high-speed transforming societies, modern heritage has been affected by being the result of a specific way of considering and building architecture, including experimenting with new materials and design appearances in use in the first half of the twentieth century, then evolving in the still understudied postwar construction industry. One of the central issues for these types of artefacts is that of ‘patrimonialisation’. The process by which elements of culture, both tangible and intangible, are transformed into defined heritage, often to preserve and promote them, involves recognising, selecting, and assigning cultural value to specific objects, practices, or places, and then integrating them into heritage institutions or systems. Contributions demonstrate that, from the initial research experiments in all three areas to the present day, considerable progress has been made; however, much remains to be accomplished. The cooperation typical of a multidisciplinary approach to knowledge, increasingly adopted as a scientific and ethical orientation towards the restoration, redevelopment, and reuse of cultural heritage, constitutes the most effective and sustainable way to accompany these ‘different’ assets towards a new contemporary dimension capable of incorporating, without denying, the historical and testimonial values of their past.