In "The Promise and Practice of Next Generation Assessment," David T. Conley presents the case for a new, comprehensive system of assessment using different measurements for different purposes. Changes in the purposes of education, he argues, demand forms of assessment that go beyond merely ranking students to supporting the ambitious aim of helping all students meet career and college readiness goals. More Conley describes the interplay between assessment and learning, and shows how "next generation" approaches can produce results that are more effective in informing classroom instruction. Acknowledging the complexity and limitations of many of these novel approaches, he suggests that rather than relying on a system built on a single measure--high-stakes, multiple-choice tests--what is needed is a system that draws on a more diverse portfolio of personalized assessments. Conley provides several examples of programs, schools, and districts that are piloting next generation approaches, and describes the opportunities and implementation challenges involved in making this shift. With decades of experience in learning and assessment, Conley outlines how next generation models can support ambitious learning for all students.