This book is intended for researchers and students in the field of second language (L2) acquisition. As its title suggests, the book discusses L2 vocabulary acquisition, knowledge and use, and examines them from the perspectives of assessment and corpus analysis. The chapters also address some additional central research issues: the role of word frequency in the input, the difference between single words and multiword units, and the distinction between vocabulary of oral and written language. The first three chapters of the book present critical reviews of different aspects of vocabulary acquisition. The other four chapters contain empirical studies that relate to the central themes of the book. The data in the studies draw on a variety of source and target languages: English, French, Italian, Swedish, Hebrew and Japanese. The book offers some new insights into the field of vocabulary and suggests avenues of research.