This book identifies and surveys the major themes around ‘out-of-field teaching’, that is, teaching subjects or year levels without a specialization. This has been an issue in many countries for some time, yet until recently there has been little formal research and poor policy responses to related problems. This book arises out of collaborations between members of an international group of researchers and practitioners from Australia, Germany, Ireland, England, South Africa, Indonesia and the United States. Cross-national comparisons of ideas through case studies, descriptions of practice and research data interrogates the experiences, practices, and contexts relating to out-of-field teaching. In particular, the book considers the phenomenon of out-of-field teaching in relation to national policy contexts, local school leadership practices, professional development. The book represents an essential contribution on a highly topical issue that has implications for quality and equitable education around the globe.