In this concise and accessible book, Scott Thornbury draws on decades of research and his own experience to provide a guide to developing effective lessons. The book begins with a discussion of the factors which influence lesson design, before offering guidance on a wide range of topics including using online resources and AI in lesson planning, designing learner-centred lessons, lesson implementation and testing and evaluation. Scott Thornbury's 66 Essentials of Lesson Design is an essential reference for teachers of all levels of experience, working in all contexts.