Intellectual property rights – copyrights included – are designed to create a market for ideas and expressions. Without them, the argument goes, there is no way

of earning money from a work or product, and so no incentive to create. The right to enjoy the material benefits of a work – if not copyright per se – is of course protected in the Universal Declaration of Human Rights.

But what happens when traditional means of earning money – through selling books or licensing files – no longer work? For every book or song that continues to sell years after publication, there are thousands, if not more, which have been forgotten, lost in a back-catalogue (or, in the digital world, simply deleted).

What opportunities are there then for creators to be rediscovered, and for their work to inspire further innovation and creativity? How can we avoid a sub-optimal situation for both authors and readers – a market failure?

Just as copyright provides a response to the need to ensure that creators can earn a living from their work, the public domain delivers on the right of society as a whole to access culture, information and knowledge. It also places limits on the harm that can be done by market failures associated with long copyright terms (many would argue too long). It is open and available to all because we don’t know – and cannot predict – who is going to rediscover which work and when. But it is better to create an opportunity, than not at all.

Libraries play an essential role both in ensuring that we have a public domain, and in increasing the chance that it will be used.

First of all, the survival of works through the long wilderness years often depends on public interest collection and preservation policies. When a purely commercial operator would have cleared copies from the warehouses or servers, libraries collect and conserve works, for example through legal deposit schemes. They then invest time, resources and expertise into keeping documents readable and usable, for the benefit of researchers and readers now and in the future. Much of the public domain as we know it lives in (or originates) from a library.

Secondly, libraries organise – by cataloguing and referencing – works in the public domain, so that they can be found and used in future. They are the original search engines, and for works created before the digital age (and many created since), the efforts of librarians and archivists in ensuring that books and other materials are recorded properly is essential.

Finally, there is access. Libraries are also about ensuring that works and the information they contain is accessed and used. By welcoming students, researchers, writers, and the general public, they provide a space where people can discover and enjoy the public domain. The Internet has offered new possibilities. The work of organisations like Europeana show what is possible when you bring together the work of libraries in one continent, and invest in user friendly web portals. Digital libraries are appearing in various countries around the world, supporting access to and exchange of works, and helping prove the diversity of our past.

Clearly there are challenges. The explosion of digital content has not been accompanied by equally ambitious preservation efforts as yet, meaning that many works are at risk of disappearing for ever. On a more political level, the dream that big data techniques will somehow make it possible to ‘monetise’ the back catalogue could lead to challenges to the public domain. But these do not affect the underlining issue – that the public domain helps limit the market failures created by copyright terms, and that libraries in turn make the public domain meaningful.