Digital software platforms such as iOS or Android evolve quickly. Through regular updates, their set of built-in (core) features increases. While innovation allows strengthening platforms amidst competition, it can hurt contributors when introducing core features that are already provided by third-party developers (Platform Coring). This book addresses the underexplored phenomenon of Platform Coring and provides strategical guidance for platform owners and third-party contributors. Platform owners are well-advised to carefully consider the benefits and risks for their platform ecosystem. The book contributes by highlighting avenues to employ Platform Coring for the competitive advantage of the platform and ecosystem simultaneously.