Ioulios Polydeukes, more commonly known as Pollux, was a Greek sophist and lexicographer active in the closing decades of the second century a.d. His Onomasticon is one of the most important lexicographical texts of the Imperial period. It is essentially a set of word lists dedicated to collecting clusters of related words on topics from a vast range of different areas of intellectual activity and everyday life. The text survives only in epitomized form, and shows signs of interpolation as well as abridgement. Nevertheless, the consensus is that the bulk of what survives is Pollux’ own work, and that reading it in Eric Bethe's Teubner edition gives an accurate cumulative impression of Pollux’ standard procedures and preoccupations, even if we cannot be entirely confident that any particular cluster of words had exactly the same form within the text's original design. It is divided into ten books, each with its own dedicatory preface addressed to the Emperor Commodus. Each book has its own distinctive focus on certain key themes, although the ordering principles are much clearer in some than in others.