Book excerpt: This book addresses global and subnational issues concerning the world's forests, societies, and environment from an independent and non-governmental point of view. Cooperation on a global scale is not only commendable, it is essential if solutions to the problems facing the world's forests are to be found. To achieve this, modern science needs to draw a clearer picture of relationships between forests, human activity, and the environment, and of the consequences of environmental change for the societies' development and growth. There are several - partly intermingled - evolutionary forest transitions underway: the slow transition from forest area decrease to an increase in the North while deforestation and degradation continues in the South. Although not all deforestation is considered negative, serious social, economic, and environmental costs may be associated with excessive deforestation. Deforestation control is just the first step on the stony path towards sustainable forest management. The forest management transition refers to the shift in the utilization towards managed semi-natural, secondary forests and plantation forests. There are some signs in the North of the forest paradigm shift from sustainable yield to forest ecosystem concepts. How deforestation can be tackled and how these concurrent transitions are effected will have profound implications for the future. These processes involve several challenges with South-North dimensions. A search for an optimum mix of public policies and markets is a global priority both as a forest policy issue and as an inter-sectoral item on the political agenda. Deforestation and transition is discussed here by a team of 14 scientists from both the North and the South. This book offers knowledge, facts, and information about world forests, society, and environment to help us towards equity in our use of the global forest – to create a clearer vision of unasylva.