Joe Overton, policy change expert and creator of the 'Overton Window', discusses how ideas can become policy. The podcast explores the significance of the 'Overton Window' concept in policy change and the role of think tanks in developing politically impossible ideas. It also delves into historical examples and current debates, while highlighting the power of persistence and the impact of the 'Overton Window' shift on policy change. The legacy of Joe Overton's concept as a teaching tool in understanding policy-making is also explored.