This collection of essays was written in honour of David Vaver, who recently retired as Professor of Intellectual Property and Information Technology Law and Director of the Oxford Intellectual Property Research Centre at the University of Oxford. The essays, written by some of the world's leading academics, practitioners and judges in the field of intellectual property law, take as their starting point the common assumption that the patent, copyright and trade mark laws within members of the 'common law family' (Australia, Canada, Israel, Singapore, South Africa, the United Kingdom, the United States, and so on) share some sort of common tradition. The contributors examine, in relation to particular topics, the extent to which such a shared view of the field exists in the face of other forces that are producing divergence. The essays discuss, inter alia, issues concerning court practices, the medical treatment exception, non-obviousness and sufficiency in patent law, originality and exceptions in copyright law, unfair competition law, and cross-border goodwill and dilution in trade mark law.