"Precautionary Rights and Duties of States goes beyond the traditional writings on this complex principle and brings new foresight on its legal implications. The book is a must for every international lawyer involved at the academic level and in practice. Arie Trouwborst’s contribution to the legal understanding of this post-modern principle will remain a classic in public international law doctrine as it shows the what, where, when and how of precautionary action in the international legal order." - Makane Moise Mbengue, in: RECIEL 17 (2) (2008)