The sharing economy is just one of several possible expressions to designate the complex model of social and economic relationships based on the intensive use of digital technology. Constant permutations and combinations allow these relationships to be established through the intervention of a third party making traditional contractual positions flexible in such a way that today’s employee is tomorrow’s entrepreneur, or today’s consumer is tomorrow’s supplier of goods and services. The current legal framework is, in many respects, unable to accommodate such big changes and new legal regulations are required where adaptation of the existing ones proves to be inadequate. This book highlights where changes are needed and where adaptations are required, with a particular focus on the Portuguese, Spanish, Italian, British and Brazilian contexts. For that, four different approaches are undertaken, namely the meta-legal, macro-legal, micro-legal and transnational approaches. The study that results from these different approaches enables readers to acquire a general view on the current legal problems arising from the sharing economy, and was a direct result of a research project of the Centre for Legal and Economic Research, at the University of Porto, funded by Fundação para a Ciência e Tecnologia.