The distinction between in-house and ex-house providing is fundamental and is well known in practice and theory. It is of utmost importance, as the consequence of the categorization of an arrangement as "in-house" is, that it falls outside of the scope of the EC public procurement rules. However, for various reasons, it is often very difficult to establish whether an arrangement is in-house or not. The case law from the European Court of Justice on this subject is highly complex, whereas the case law at national level is sparse. Furthermore, the legal literature both at national and international levels has been relatively limited. This book deals with in-house in a broader perspective and looks into the interpretation, implementation, and practice at the national level in a range of Member States. This book is the first in the new European Procurement Law series, which will contribute to a strengthened dialogue between the various legal cultures in the field of procurement.