This book investigates under which circumstances vertical unbundling can lead to a more efficient market result. The assessment is based on an interdisciplinary approach combining law and economics. Drawing on the assessment, circumstances are subsequently presented under which unbundling might become necessary. Additionally, less severe means of regulatory intervention are suggested in order to protect competition. Given its scope, the book is chiefly intended for scholars and practitioners in the field of economic policy and regulation law; in addition, it will give interested members of the public a unique opportunity to learn about the underlying rationales of regulation law and regulation economics.