Decoherence, the measurement problem, and interpretations of quantum mechanics Maximilian Schlosshauer Decoherence and superselection have been subjects of intense research over the past two decades, yet their implications for the foundational problems of quantum mechanics, particularly the measurement problem, remain controversial. This paper clarifies key features of the decoherence program, including recent results, and investigates their application and consequences in the context of main interpretive approaches of quantum mechanics. The measurement problem involves reconciling quantum superpositions with classical observations. It includes the problem of definite outcomes and the preferred-basis problem. Decoherence addresses these by studying the formation of quantum correlations between a system and its environment, leading to the suppression of interference between preferred states. Decoherence is often associated with the emergence of classical properties through interaction with the environment. The decoherence program studies the effects of system-environment interactions within standard quantum formalism. It includes the resolution into subsystems, reduced density matrices, a modified von Neumann measurement scheme, and environment-induced superselection. Decoherence leads to the selection of pointer states, which are robust against environmental interactions and correspond to classical properties. Decoherence has implications for various interpretations of quantum mechanics, including the Copenhagen interpretation, relative-state interpretations, modal interpretations, physical collapse theories, Bohmian mechanics, and consistent histories. While decoherence provides insights into the measurement problem, it does not fully resolve it. The role of decoherence in these interpretations varies, with some interpretations using it to motivate basic postulates of quantum mechanics. The decoherence program has made significant progress, but its limitations in providing consistent answers to foundational questions must be acknowledged. Decoherence explains the appearance of classicality but does not fully resolve the measurement problem. The debate over decoherence's role in quantum mechanics continues, with ongoing discussions about its implications for the foundations of quantum theory.Decoherence, the measurement problem, and interpretations of quantum mechanics Maximilian Schlosshauer Decoherence and superselection have been subjects of intense research over the past two decades, yet their implications for the foundational problems of quantum mechanics, particularly the measurement problem, remain controversial. This paper clarifies key features of the decoherence program, including recent results, and investigates their application and consequences in the context of main interpretive approaches of quantum mechanics. The measurement problem involves reconciling quantum superpositions with classical observations. It includes the problem of definite outcomes and the preferred-basis problem. Decoherence addresses these by studying the formation of quantum correlations between a system and its environment, leading to the suppression of interference between preferred states. Decoherence is often associated with the emergence of classical properties through interaction with the environment. The decoherence program studies the effects of system-environment interactions within standard quantum formalism. It includes the resolution into subsystems, reduced density matrices, a modified von Neumann measurement scheme, and environment-induced superselection. Decoherence leads to the selection of pointer states, which are robust against environmental interactions and correspond to classical properties. Decoherence has implications for various interpretations of quantum mechanics, including the Copenhagen interpretation, relative-state interpretations, modal interpretations, physical collapse theories, Bohmian mechanics, and consistent histories. While decoherence provides insights into the measurement problem, it does not fully resolve it. The role of decoherence in these interpretations varies, with some interpretations using it to motivate basic postulates of quantum mechanics. The decoherence program has made significant progress, but its limitations in providing consistent answers to foundational questions must be acknowledged. Decoherence explains the appearance of classicality but does not fully resolve the measurement problem. The debate over decoherence's role in quantum mechanics continues, with ongoing discussions about its implications for the foundations of quantum theory.