This chapter explicates the rationale for focusing on science and engineering practices and traces the development of this idea from earlier notions of inquiry in science. In going from the Framework to the Next Generation Science Standards (NGSS), the expectations of what students might achieve will not be framed solely in terms of what students should know but also what students should be able to do. We see this as potentially a major transformation in the teaching of science. Our hope is that the vision of science offered by the Framework and the NGSS will be a means to offer students more of these kinds of experiences and to give them the thrill and liberation that comes from the understanding that science is a means of creating new knowledge. A list of materials, teacher background information, standards, assessment, and references are provided. This book selection also includes the Table of Contents, About the Editors, Contributors, Acknowledgments, and Index.