This book focuses attention on mathematics learners in transition and on their practices in different contexts; on the institutional and socio-cultural framing of the transition processes involved; and on the communication and negotiation of mathematical meanings during transition. The book offers both empirical studies and significant theoretical reflections from a socio-cultural perspective, with the aim of providing the bases for the development of more socially and culturally responsive mathematics learning environments. It will appeal to researchers and postgraduate students in the fields of mathematics education, cultural psychology, multicultural education, immigrant and indigenous education.