A World in Transition, Humankind and Nature is appropriately entitled after its aim for an intrinsic property of reality: change. Of major concern, in this era of transformation, is the extensive and profound interaction of humankind with nature. The global-scale social and technological project of humankind definitely involves a myriad of changes of the ecosphere. This book develops, from the call for an interdisciplinary synthesis and respect of plurality, acknowledging the evolving scientific truth, to the need for an integrated but inevitably provisional worldview. Contributors from different parts of the world focus on four modes of change: (i) Social change and the individual condition, (ii) Complex evolution and fundamental emergent transformations, (iii) Ecological transformation and responsibility inquiries, (iv) The economic-ecological and socio-technical equilibria. Primarily concerned with the deep transformations of humankind and of the relationship between humans and nature, it is addressed to a broad and thinking public that wants to be kept informed.