Learning new words is foundational to success in school and life. Researchers have known for years that how many word meanings a student knows is one of the strongest predictors of how well that student will understand text and be able to communicate through writing. This book is about how children learn the meanings of new words (and the concepts they convey) and how teachers can be strategic in deciding which words to teach, how to teach them, and which words not to teach at all. This book offers a comprehensive approach to vocabulary instruction. It offers not just practical classroom activities for teaching words (though plenty of those are included), but ways that teachers can make the entire curriculum more effective at promoting students' vocabulary growth. It covers the 'why to' and 'when to' as well as the 'how to' of teaching word meanings.