Building and sustaining a successful school learning climate has since long been regarded a pivotal task of educational leaders and a vital lever to improve student learning and achievement. How to build such learning-oriented climates pervades discussions on education around the globe, and current trends in educational leadership and administration foreground the importance of principals' social relationships in shaping such learning climates. In recent years research has expanded its scope beyond the student to investigate how educators' relationships shape school climates, and various studies have suggested that social interactions among educators are vital to productive learning climates, both in terms of student learning and teachers' professional development. Teachers, whether they are traditional classroom teachers, school management team members, or district colleagues, form an important part of the social context of schools within which principals administrate. Principals are greatly dependent on their teachers to reach school goals, as teachers form the bridge from administration to classroom. To better understand social relationships among principals and teachers, we have brought together several studies in this eBook that each highlight a different, yet related aspect of these relationships. The studies focus on how principals' social relationships foster or constrain the quality of school learning climates in schools among a variety of school settings around the world. Five research papers scaffold a comprehensive framework of how principals' social relationships affect school learning climates. Each paper examines nuanced portions of this framework, and together, the papers are intended to form an overall understanding of this important topic. The contributions draw on data from three countries, and employ rigorous, novel, and theoretically motivated methods in order to offer a comprehensive perspective on principal-teacher relationships in different settings, countries, and with different types of teacher professionals. A number of techniques are employed to test the key theoretical underpinnings regarding the centrality of the principal in shaping the school learning climate, and we aim to contribute rigorous empirical work to support theory-building on fostering and sustaining productive professional social workspaces to benefit school learning climates. This eBook also includes, as well as the empirical studies, two commentaries from leading scholars in policy, research, and praxis of school leadership and school learning climates. In sum, this collection of papers offers a strong and unique contribution to understanding the impact of principals' social relationships by using multiple theoretical perspectives, drawing on a variety of data collection and analysis methods, studying these relationships in multiple educational settings and countries, and examining the impact of these relationships at both individual and organizational levels. Taken together, these papers provide a comprehensive understanding of principal-teacher relationships as they support the work of shaping school learning climates around the world.