1. Introduction -- 2. Business Aspects of the Spare Parts Industry -- 3. Design Protection Relating to Component Parts of Complex Products (Spare Parts) in the EU and the U.S. -- 4. Legislative Efforts Relating to Design Law in the Context of Spare Parts -- 5 Jurisprudence Relating to Design Law in the Context of Spare Parts -- 6. Considerations Towards a Compromise -- 7. Future Outlook: The Spare Parts Debate in the Era of 3D Printing -- 8. Conclusion. .This publication examines the legal aspects of the spare parts market from an IP perspective: specifically whether design protection for spare parts of a complex product extends to the spare part aftermarket, or whether that market should remain open to competition. The stakeholders’ equally weighty arguments that must be balanced against are, on the one hand, the property interest in an earned IP right in the design of the part; and on the other, enhanced competition, likely reflected in lower prices. The mounting tension between these two positions is manifest an increased number of lawsuits in both the US and the EU. This book provides a discussion of the legal issues involved in this debate from a global perspective, with special focus on the EU and the US. Part I contextualizes the legal debate by discussing the historical background, the competitive situation and the respective stakeholder positions. Part II examines the relevant legal questions on a comparative basis, evaluating the likelihood of its adoption in the jurisdictions examined. Concluding that adoption is unlikely, Part III proposes a number of possible considerations meant to further compromise. Part IV concludes with a future outlook, specifically in light of the impact of technological development on this market.