Operating under the auspices of the Human Rights Council, the Universal Periodic Review (UPR) is an innovative mechanism in which the human rights record of all UN member states is scrutinized by their peers. Since it started functioning in 2008, not only have all states been under review for two cycles now, but they have actively participated in interactive dialogues making over 55,000 recommendations on a number of different human rights issues. A decade after its first session, an assessment of this unique mechanism becomes more relevant than ever. This chapter examines the principles and practices on key features of the UPR, such as universality, equal treatment, the peer-to-peer element, international cooperation and dialogue. It argues that the interplay of these characteristics turns the UPR into a distinctive horizontal pathway to impact, which is unique in the international human rights regime.