This book describes a new pedagogical approach to learning design by intentionally designing and incorporating errors into learning experiences. DELETE¿ stands for Designing Errors for Learning and Teaching and it is an approach that targets the roles that errors can play in establishing the contextual boundaries of rules and operating procedures for learners. With clarity of boundaries, learners understand the context under which rules apply and don't apply, resulting in the development of competencies and capabilities and, subsequently, expertise. DELETE¿ as a methodology is useful for developing cognitive, affective, social and metacognitive capabilities in ways which are different from typical training pedagogies, focusing on contextual boundaries that enable application of concepts besides the concepts themselves, while typical training pedagogies focus on teaching the concepts. The book provides stories and experiences as well as actual resources (e.g., case studies, critical incidents, Math problem sums) demonstrating the use of DELETE¿ when designing lesson plans, learning resources and assessment items.