This book analyses, clarifies, and discusses which positive obligations derived from EU law, in a public procurement law context, a contracting authority must apply when entering into one of the three types of contracts - service concession contracts, contracts below the thresholds and contracts regarding B-services, and how these obligations can be enforced. Thus, it analyses, which obligations can be derived from mainly the Treaties' principle of transparency and the principle of equal treatment when a contracting authority enters into one of the three types of contracts. Furthermore, it analyses how these obligations can be enforced. Effective remedies are essential to ensure that contracting authorities behave in accordance with the obligations derived from the principles of the Treaties, when entering into one of the three types of contracts. If the principles can be infringed without repercussions, the effectiveness of the principles will be endangered. Thus, effective remedies must be available when the principles have been breached.