What meaning and potential could be offered by performance in the age of ecological crises, climatic change and the sixth extinction? Tuija Kokkonen responds to this core question from various perspectives with particular inspiration from Felix Guattari'sThree Ecologies(1989) and the author's artistic work on ecology and performance. Ecological crises are understood and explored as wider phenomena emerging in three ecological levels - the mental, the social and the environmental - cohering with and affecting each other.Cutting across areas of artistic research and performance philosophy, as well as engaging in post-humanism, animal studies, and plant philosophy, the central concern of the book is our relationship to the non-human and what it means to our understanding of performance and subjectivity if the agency of performance and its social area are opened to non-human co-actors, to beings of other species, to animals, plants and weather. These performances as well as the concepts and thoughts arise from a performance practice described - echoing Michal Marder's plant thinking (2013) - as performance-thinking, partly a non-cognitive, embodied way of thinking about and with performance. Through agencies of animals, plants and weather, the book also explores the borders of performance, and of human being. In this book, five key performance studies terms and questions are addressed - human centeredness, liveness, spectatorship, event and performance - and are rethought in the context of posthuman performance practice and theories. Furthermore, some unknown or less familiar philosophers, especially in the field of environmental philosophy are introduced, such as the Czech philosopher Erazim Kohák, Finnish philosophers Yrjö Haila and Ville Lähde, and Hans Jonas as a philosopher of environment ethics.