This special issue includes 5 contributions of contemporary work based in the phenomenography and variation theory research tradition and also actualises theoretical and methodological discussions. This introduction consists of 3 main parts. First is a brief introduction to and framing for the contributions through pointing to some of the main points made and putting them in perspective in the tradition. Second, the use and meanings of 4 key terms in the tradition--phenomenon, object of learning, dimension of variation, and critical aspect--are analysed across the contributions. Third, and finally, possible emergent strands of future research based in phenomenography and variation theory are discussed, and how the contributions relate to and are reflective of such emergent strands.