This article offers reflections on contemporary debates in policy studies. It starts by mapping the contours of the terrain covered by Policy & Politics over the last 40 years. It does so under four headings: (1) theorising policy (2) evidence and the policy process (3) transforming structures and processes and (4) implementation and practice. It then uses these headings to draw out themes from the articles comprising this 40th anniversary special issue. We conclude by arguing for greater tolerance of diversity in theoretical and empirical enquiry and for continued reflection on the foundational assumptions of the field of policy studies.