The Okinawan-English Wordbook, written by the late Mitsugu Sakihara, historian and native speaker of the Naha dialect of Okinawa, is an all-new concise dictionary of the modern Okinawan language with definitions and explanations in English. The first substantive Okinawan-English lexicon in more than a century, it represents a much-needed addition to the library of reference materials on the language. The Wordbook opens to lay user and linguist alike an area heretofore accessible almost exclusively in Japanese works and adds to the general body of scholarship on various Ryukyuan languages and dialects by providing a succinct but comprehensive picture of modern colloquial Okinawan. The current work comprises nearly 10,000 entries, many with encyclopedic discussion, drawn from a wide variety of sources in addition to the author's native knowledge and from numerous areas of interest, with emphasis on the cultural traditions of Okinawa. Entries reflect both contemporary Naha usage and archaisms and areal variants when these are of cultural, historical, or linguistic interest. Thus, in addition to being a comprehensive portrait of the modern Okinawan language, the Wordbook serves as an implicit introduction to the rich field of Japanese dialect studies. Prefatory material discusses the phonology of Okinawan and the romanization scheme employed in the book, with particular attention to phonological features of the language likely to be unfamiliar to native English speakers and those acquainted only with Japanese. A general introduction to the conjugation of verbs and adjectives in Okinawan is made as well.