For over forty years we have witnessed the development of a European Law of public procurement that seeks the biased harmonization of the national legislation of each Member State, with the purpose of guaranteeing a free and equal competition in this important European business sector. It is an ambitious legal challenge that has forced the legislators of the twenty-seven Member States to modify their internal regulation in order to adapt it to the European Directives and that has lead to an extensive and rigorous jurisprudence, either of the Court of Justice of the European Union or of the National Courts of each Member State. The present book studies the above mentioned European Law of public procurement in a realistic and practical way, examining both the jurisprudence of the Court of Justice and the Law itself that the Member States have approved and apply. Studies of this kind allow us to check, on one hand, which are the legal problems that the harmonisation process of the public procurement regime is facing and, on the other, the different ways of integration of the Guidelines in the different States Law, according to their own legal and administrative traditions. Beyond its comparative interest, it allows to go into the national legislation on the matter to all those for whom it could be of interest or utility, be them attorneys, lawyers, companies or specialists of Public Law.