Vocabulary development is critical for children's ability to learn to read and their success at school. Vocabulary has also been identified as a key factor in the achievement gap, with children from low-income families knowing significantly fewer words when they enter school. Although book reading has long been celebrated as an effective way for teachers to introduce children to vocabulary words, teachers have received little specific guidance about exactly which strategies are most effective for teaching children words. In this paper, we review the literature on book reading-focused vocabulary interventions for preschool- and kindergarten-aged children. Findings suggest that teachers should focus on five strategies that boost word learning through book reading, including defining words, discussing and asking questions about the words, rereading books, retelling books, and designing classroom activities that allow children to hear and use new vocabulary throughout the day.