This volume is a retrospective publication of contributions originally to two national conferences / seminars held in Sheffield, on the theme of ‘Urban Environments - History, Biodiversity and Culture’. To the updated papers from those events we have added invited current contributions on the themes of urban nature and urban ecology. Ideas and issues in urban ecology become more significant as globalisation, urbanisation and cultural severance shape our world and our future ecologies. This is paralleled by increasing interest in the underpinning science and research paradigms in relation to urban environmental spaces.In the early 2000s, ecologists new to the urban context suddenly became excited about the juxta-position of pollution and biodiversity in degraded and contaminated sites, something well-known to urban ecologists and naturalists since the 1980s or earlier. Similarly, the contributions of urban gardens to nature conservation were greeted with surprise and excitement.