Introduction -- Constructive deviance: what is DIY urban design? And what is it not? -- Individualizing civic responsibility: DIY urban design in the help-yourself city -- "I'm an expert on public space": professional and scholarly knowledge at work in DIY urbanism -- The spatial reproduction of inequality: social privilege and disadvantage in creative transgression -- Pop-up planning: from park(ing) day to parklet dining, DIY goes official -- Conclusions