The ‘secret language’ of the title of this book covers many kinds and levels of secrecy (things hidden and concealed), and a similar range of languages. The reasons for secrecy in language are manifold, the book argues, and Barry Blake gathers into his survey a vast range of material that illustrates how people can be oblique or indirect in their uses of language, which can be characterised by the blanket term ‘secret’. While the primary focus is on English, Blake often uses examples from past languages (Latin, Greek, Old Norse), from geographically dispersed languages spoken today, and especially from the Australian Aboriginal languages that were his field of expertise when Professor of Linguistics at La Trobe University.