Nicholas Onuf’s International Legal Theory: Essays and Engagements 1966-2007 is a collection of the author’s articles and book reviews from the period, including some previously unpublished material. The book records the author’s efforts to address important problems in international legal theory and to engage other scholars who were also addressing these problems. As well as demonstrating Onuf’s own constructivist contribution to the theoretical dimension of international law and international relations, each piece is preceded by a short introduction which highlights the wider themes and developments which have occurred in the field of international law in the last forty years.