The Idiom Book was written for high-intermediate/advanced young adult and adult learners of English. The language used is very colloquial and is intended to represent the authentic linguistic expression of native speakers interacting socially in informal personal and professional contexts. Each lesson features 10 idioms. The book is divided into 101 lessons, with each lesson having four sections: - Section A introduces the idioms in the context of an idiomatic conversation. - Section B presents the same idioms in a different format, most in the form of written messages. The messages are gapped. Section C uses a matching exercise to increase the learning challenge. Section D has the students using the idioms in a given sentence substituting the idiom for a non-idiomatic phrase. The topics are varied and interesting. There is a list of idioms and an answer key available for download at ProLinguaLearning.com. An optional downloadable audio program for this book is also available.