* _Space Law: Cases and Materials_ (1994)
* _The Global Common Interest: Philosophical Foundations and International Law_ (1998)
* _Beyond the Moon: International Law in Space_ (2004)
* _International Space Law: A Policy Orientation_ (2nd edition, 2008)
* _Legal Framework for Space Tourism: A Comparison with Aviation and Other High Risk Industries_ (2010)
* _Space Law and Policy Towards 2030_ (2012)
* _Space Technology for Sustainable Development: A Comparative Perspective_ (2014)
Philosophy
* _The Ethics of Space Exploration_ (2004)
* _Morality and War in the Contemporary World_ (2010)