This book assesses how contractual promises are expressed in software and how code-based artefacts can be incorporated within more conventional legal structures. With incisive contributions from members of the judiciary, legal scholars, practitioners, and computer scientists, this book sets out to frame the borders of an emerging area of law and start a more productive dialogue between the various disciplines involved in the evolution of contracts as software. It provides the first step towards a more disciplined approach to computational contracts that avoids the techno-legal ambiguities of 'smart contracts' and reveals an emerging taxonomy of approaches to encoding contracts in whole or in part. Conceived and written during a time when major legal systems began to engage with the advent of contracts in computable form, and aimed at a fundamental level of enquiry, this collection will provide essential insight into future trends and will provide a point of orientation for future scholarship and innovation.