The ID CaseBook provides instructional design students with 25 realistic, open-ended case studies that encourage adept problem-solving across a variety of client types and through all stages of the process. After an introduction to the technique of case-based reasoning, the book offers four sections dedicated to K–12, informal learning, post-secondary, and industry clients, respectively, each comprising varied, detailed cases created by instructional design experts. All cases, alongside their accompanying discussion questions, encourage students to analyze the available information, develop action plans, and consider alternative possibilities in resolving problems. This revised and updated sixth edition attends to the profound impacts that public health crises; urgent access, equity, and inclusion needs among diverse learners; and a rapidly expanded reliance on digital learning formats have had on the design of learning today.