This document summarizes principles of materials design for language teaching. It discusses six principles identified by David Nunan, including linking materials to curriculum goals, using authentic texts and tasks, stimulating interaction, allowing focus on language forms, developing learning skills, and applying skills outside class. It also outlines 16 principles by Brian Tomlinson, such as achieving impact, helping learners feel at ease, developing confidence, and perceiving relevance. The document contrasts authentic materials produced for genuine communication versus created materials designed for language learners. It provides examples of authentic materials like radio broadcasts and definitions from various scholars.