Book Review: Negotiating Brexit, edited by John Armour and Horst Eidenmüller. (Munich/Oxford/Baden-Baden: C.H. Beck/Hart/Nomos, 2017); The UK after Brexit. Legal and Policy ChallengesNegotiating Brexit, edited by John Armour and Horst Eidenmüller. (Munich/Oxford/Baden-Baden: C.H. Beck/Hart/Nomos, 2017); The UK after Brexit. Legal and Policy ChallengesNegotiating Brexit, edited by John Armour and Horst Eidenmüller. (Munich/Oxford/Baden-Baden: C.H. Beck/Hart/Nomos, 2017); The UK after Brexit. Legal and Policy Challenges