Building on Jack Richard's interest in vocabulary, this paper looks at the importance of morphology (how words are formed) in language learning and teaching. It describes why knowledge of morphology is important, and how it affects vocabulary learning. It provides clear guidelines on what word parts to focus on, how much time to spend on word parts and what a teacher (and learners) should do about word parts. Morphological knowledge involving derivational affixes becomes particularly important when learners know the first 2000-3000 words of English. One of the major activities for developing morphological awareness is cutting words into parts and relating the meanings of the parts to the meaning of the whole word. Teachers should help learners develop morphological awareness, train learners in word part strategies, and help learners to learn frequent word parts. The paper includes activities to achieve these goals in the classroom, as well as links that provide material for classroom use.