Introduction In University of London Press Ltd v University Tutorial Press Ltd , Petersen J remarked that what is worth copying is prima facie worth protecting. 1 The truth underlying this statement is demonstrated nowhere so strikingly as in the commercial exploitation of computer software. Although computers have now been in existence for well over half a century, the protection of the intellectual property rights in computer programs and software only really became a legally signifi cant issue with the later advent of microcomputers. In the early stages of development of the industry, computer systems were large, custom-built affairs, used primarily by large institutions, whether commercial, industrial or educational. If there was a need for protection of the intellectual property rights in the software and programs, then this could easily be accommodated in contractual terms, supplemented by actions for breach of confi dence if appropriate. 2 As microprocessors and personal computers became commonplace, their use became widespread and was no longer confi ned to large institutions. This, together with the accompanying trend towards general applications programs, rather than specifi c bespoke software, meant that it rapidly became impossible to rely purely on contract and confi - dence to protect intellectual property rights in computer programs. As a considerable amount of research and development time and money may be devoted to the creation of new computer software, it is not surprising that those engaged in this activity look for assurance that their intellectual property rights are protected. Although desirable for commercial reasons and the familiar justifi cation of intellectual property law as an incentive to innovation, providing such legal protection has not proved to be straightforward. A property of computer software, and a signifi cant difference from other forms of intellectual property, is its extreme vulnerability to copying. This is a direct consequence of the nature of the technology – the actual functioning of a computer is dependent on copying code backwards and forwards. It is a trivial matter therefore to make copies of software and widespread piracy is easy. In contrast to the previous chapter, this chapter will consider the way in which the intellectual property rights in computer programs have developed and the scope of the legal protection available using traditional forms of intellectual property protection.