There can be no denial of the fact that the correct application of productive language learning strategies (LLS) can facilitate language learning to a large extent. In addition, vocabulary, as the building block of language, has long been a major concern of teachers and educators. Recently, the focus has shifted from single words to multi-word units, of which idioms are of particular interest for both teachers and learners. Both LLS and idioms, as two controversy evoking areas, have been extensively investigated. However, the relationship between the two concepts has been little explored, often producing conflicting results. This book is an attempt to partially fill the existing gap. It offers a theoretical review as well as an experimental analysis of the relationship between them. It may be useful for language learners, teachers and researchers.