Rahmah Johar is a lecturer at the Universitas Syiah Kuala, Aceh, Indonesia since 1998. Her education of undergraduate, graduate, and doctor program are all about Mathematics Education. Since 2006 she has been actively developing and socializing Realistic Mathematics Education. In 2010, she received a scholarship from Dikti, the Program Academic Recharging (PAR) to design mathematics textbook collaboration with Freudenthal Institute, Universiteit Utrecht, the Netherlands. Her research interests is about the teacher professional development in teaching mathematics including helping teacher to implement RME, develop students' reasoning, students' character, democratic classroom, using video lesson, and implementation of technology. She is as an editor in chief of the Jurnal Didaktik Matematika (www.jurnal.unsyiah.ac.id/DM)