Research and scholarship into educational effectiveness research (EER) is comprehensively reviewed from the UK, The Netherlands, the US, Cyprus, Belgium, Sweden, France, Germany, New Zealand, Australia, and other societies, dating from the field's origins in the 1970s. Issues include its history, methodological and theoretical advances, scientific properties of school effects, processes at school and classroom level behind these effects, the somewhat limited translation of findings into policy and practice across the world, and future directions for research and practice in EER and for all of the discipline more generally. Future research needs are argued to be a further concentration upon teaching/teachers, more longitudinal studies, more work on possible context specificity, exploration of the cross-level transactions between schools and their teachers/classrooms, the adoption of "efficiency" as well as "effectiveness" as outcome measures, and a renewed focus upon the education of the disadvantaged, the original focus of our discipline when it began.