The fourth edition of this work represents a thorough rewrite. The chapter The Executive and the chapter Characterisation and the Trade and Commerce Power have been rewritten to provide a more straightforward structure, greater clarity, and contemporary relevance. The material dealing with human rights has been substantially restructured: the chapters dealing with the implied freedom of political communication have been rewritten to take account of new developments and to provide space for major new cases. The final chapter on constitutional change has also been reworked to include separate sections dealing with Bill of Rights issues and issues relating to an Australian republic.