The publication in 2015 of new international school library guidelines was the culmination of a two-year process involving a wide network of contributors. The process was guided by the Joint Committee of the International Federation of Library Associations (IFLA) School Libraries Section and the International Association of School Librarianship (IASL). The new guidelines remain grounded in and consistent with principles expressed in the 1999 IFLA/UNESCO School Library Manifesto. The "IFLA School Library Guidelines," 2nd edition, interpret in practical terms those foundational principles and reflect current research, practice, and conditions of 21st-century school librarianship. The second edition of the "IFLA School Library Guidelines" meant to apply to school libraries of many different kinds, and the importance of local context is addressed frequently throughout the document. All school libraries, regardless of context or placement in developed or developing countries, exist on a continuum of practice. Regardless of the context, ultimately school libraries embody the basic concept expressed in the "IFLA/UNESCO School Library Manifesto" of "teaching and learning for all." The guidelines have no force of law, only the force of persuasion or inspiration, and they need to be implemented nationally and locally through legislation and through professional practice. It is possible that the international guidelines will inspire the development of national or regional standards and/or legislation where none exists at present. "The IFLA School Library Guidelines" will need to be updated in the future. As the current educational environment continues to evolve, school libraries will evolve to address the challenges of educating current and future generations. The leaders within IFLA and IASL have a well established pattern of collaboration and a shared commitment to keeping our guidelines relevant to our rapidly changing learning environments: These school library guidelines envision a world of inclusion, equity of opportunity and social justice. They will be implemented in the context of the 21st century, characterized by change, mobility, and interconnection across different levels and sectors. (IFLA 2015, 13)