The thesis "The value of waste and the costs of disposal. Tillvaratagande, förbränning och återvinning i Stockholm 1900-1975" spans between political environmental history, consumption history and cultural history. The aim is to connect ideas about waste with the material conditions that created waste, and thereby analyze change and continuity in the practical disposal of waste in Stockholm. The change in the view of waste, and in the practice of disposal, is discussed in the thesis through the concept of waste regimes, which brings together material and discursive aspects of waste. The period 1900-1927 is characterized by a waste regime with extensive recovery. This was replaced in the 1930s by a regime based on incineration. During the 1960s, criticism was raised against incineration as the dominant practice, and in the early 1970s, small-scale practical attempts were made at recycling. The thesis thus deals with the establishment, maintenance and termination of a recovery regime, as well as the establishment, maintenance and challenges of an incineration regime. The view of waste as an asset or a liability is central to the disposal solution chosen. Waste material as a value, and disposal as a cost, have not been assessed solely on the basis of market economic conditions but also in a wider context of, for example, ideals of thrift, the pursuit of modernity or environmental awareness.