This chapter analyses two categories where voluntary acts by copyright owners create potential for use of works which fits our definition of ‘public rights’ as the ability of users to use works without first obtaining the consent of a copyright owner, and which are therefore two categories of the copyright public domain. They are voluntary licensing of works by copyright owners, using predesigned licences written by some independent third party on public interest grounds (which we call ‘neutral voluntary licensing’); and ‘relinquishment’ of copyright (also called ‘public domain dedications’). These voluntary licences are at no cost to licensees, and are usually grants of licences to the public at large, but the uses are subject to compliance with conditions set out in the particular licence. The result can be described as a ‘contractually constructed commons’. Major expansions of public rights in copyright in the last two decades have been because of such voluntary licensing, primarily though two types of such licensing: free and open source software (FOSS) licensing and open content licensing (particularly the Creative Commons suites of licences). We examine the need to strengthen these aspects of the public domain, and set out recommendations.