In this paper, we report of the major themes that emerged from the presentations and discussions of the paper and poster contributions in TWG18a+b. We identified the following overarching themes as key to the research and conference conversations in the field of pre-service mathematics teacher education and the professional development of in-service mathematics teachers and asked in particular: How can we (1) generalise from research whilst maintaining complexity? (2) best reflect our roles as mathematics teacher educators and researchers? (3) research the relationship between teacher education, professional development and classroom practice? (4) productively cross boundaries in our research? (5) better reflect the role of context? (6) make sure that our research makes mathematics sufficiently visible? Finally, we discuss how we can build on one another’s work to further develop the field and suggest possible future developments and research directions.