In this edited volume, science education scholars engage with the constructs of identity and identity construction of learners, teachers, and practitioners of science. Reports on empirical studies and commentaries serve to extend theoretical understandings related to identity and identity development vis-à-vis science education, link them to empirical evidence derived from a range of participants, educational settings, and analytic foci, examine methodological issues in identity studies, and project fruitful directions for research in this area. Using anthropological, sociological, and socio-cultural perspectives, chapter authors depict and discuss the complexity, messiness, but also potential of identity work in science education, and show how critical constructs—such as power, privilege, and dominant views; access and participation; positionality; agency-structure dialectic; and inequities—are integrally intertwined with identity construction and trajectories. Chapter authors examine issues of identity with participants ranging from first graders to pre-service and in-service teachers, to physics doctoral students, to show ways in which identity work is a vital (albeit still underemphasized) dimension of learning and participating in science in, and out of, academic institutions. Moreover, the research presented in this book mostly concerns students or teachers with racial, ethno-linguistic, class, academic status, and gender affiliations that have been long excluded from, or underrepresented in, scientific practice, science fields, and science-related professions, and linked with science achievement gaps. This book contributes to the growing scholarship that seeks to problematize various dominant views regarding, for example, what counts as science and scientific competence, who does science, and what resources can be fruitful for doing science.