Supporting new teachers is a common challenge globally and the European Commission has recently emphasised the need to promote a lifelong continuum of teachers’ professional development by building bridges between pre-service and in-service teacher education.Peer-Group Mentoring for Teacher Development introduces and contextualises for an international audience, a new model for teachers’ professional development; Peer Group Mentoring, (PGM). It is based on the constructivist view of learning, the idea of shared expertise, and the ‘Model of Integrative Pedagogy’ which emphasises the integration of different forms of expert knowledge in professional development.This book explores the theoretical and practical background for developing the peer-group mentoring model, and provides important contextual information about the Finnish school system in which it was conceptualised, and also about teacher education. It presents several empirical studies on applying the PGM model with primary and secondary school teachers in different school contexts, and outlines future challenges; examining peer-group mentoring in the framework of wider practice architectures of teacher education. The book is an indispensable reference tool for educationalists and education researchers interested in collaborative and dialogic learning, teacher professional development and school administration.