Reflecting current understanding of vocabulary as a multifaceted construct, this edited volume presents a collection of qualitative and quantitative studies which shed light on key theoretical concepts associated with learning and using vocabulary in second language contexts. Themes explored in the volume include the concept of partial vocabulary knowledge, the relationship between reading ability and vocabulary knowledge, the specialised vocabulary of high school science, morphological and orthographical components of word learning, the impact of word aspects on difficulty of learning, the nature of affix knowledge, and early speech development. The findings presented in the volume contribute to our growing and deepening appreciation of the contribution of vocabulary knowledge to learning and using language in second language contexts.