Fifty years ago, Richard Sennett wrote his groundbreaking work 'The Uses of Disorder', arguing that the ideal of a planned and ordered city was flawed, likely to produce a fragile, restrictive urban environment. 50 years later, Sennett returns to these still fertile ideas and alongside campaigner and architect, Pablo Sendra, sets out an agenda for the design and ethics of the Open City. The public spaces of our cities are under siege from planners, privatisation, and increased surveillance. Our streets are becoming ever more lifeless and ordered. What is to be done? Can disorder be designed? Is it possible to maintain the public realm as a flexible space that adapts over time? In this provocative essay Sendra and Sennett propose a reorganisation of how we think and plan the social life of our cities.