The article discusses the ensemble nature of allostery, a process where the binding at one site of a biological macromolecule (usually a protein) influences the activity of another distal site. Recent studies have shown that dynamic and intrinsically disordered proteins can facilitate allostery, challenging traditional static structural models. The authors review the historical development of allosteric concepts, from early models like the KNF and MWC to more recent insights into the role of conformational dynamics and disorder. They highlight that allosteric mechanisms are often more statistical and less deterministic, involving a wide range of conformational states and interactions. The article emphasizes the importance of considering allosteric proteins as ensembles of states, where the overall activity is a weighted average of all possible states. This ensemble perspective reveals a rich spectrum of regulatory strategies and unifies descriptions of allosteric mechanisms across different systems, including structured, dynamic, and disordered proteins. The authors also discuss the implications of this ensemble view for experimental techniques, protein design, and evolutionary studies.The article discusses the ensemble nature of allostery, a process where the binding at one site of a biological macromolecule (usually a protein) influences the activity of another distal site. Recent studies have shown that dynamic and intrinsically disordered proteins can facilitate allostery, challenging traditional static structural models. The authors review the historical development of allosteric concepts, from early models like the KNF and MWC to more recent insights into the role of conformational dynamics and disorder. They highlight that allosteric mechanisms are often more statistical and less deterministic, involving a wide range of conformational states and interactions. The article emphasizes the importance of considering allosteric proteins as ensembles of states, where the overall activity is a weighted average of all possible states. This ensemble perspective reveals a rich spectrum of regulatory strategies and unifies descriptions of allosteric mechanisms across different systems, including structured, dynamic, and disordered proteins. The authors also discuss the implications of this ensemble view for experimental techniques, protein design, and evolutionary studies.