Marilar Jiménez Aleixandre is science education Professor in the University of Santiago de Compostela, Spain. A former high-school biology teacher, involved in innovation, she was part of the first batch of Spanish researchers completing doctoral dissertations in science education around 1990 (hers on conceptual change about evolution) and building a community around this field in Spain. She has also served as coordinator of science teacher development for Spain, with particular attention to programs to involve girls in science. Her ongoing research program explores the development of argumentation, evidence evaluation and critical thinking in the science classroom, through authentic problems and socio-scientific issues, as determinism. In the last years this program has evolved to the examination of students' enactment of epistemic practices and how to support them. She has also participated, as an argumentation expert, in several EU funded projects about IBST. She has been recipient of several Spanish awards, for her PhD thesis and for her publications. She has authored about 45 books or book chapters on argumentation, environmental education and biology education. She has also published about 60 papers in refereed journals, in English, Spanish, French and Portuguese.