The mission of the Jacobs Foundation is to foster children and youth development. It does this by supporting institutions and projects that contribute to the welfare, social productivity, and social inclusion of current and future generations of young people by understanding and promoting their personal development and employability, their respect for and integration with nature and culture, and the challenges posed by social, economic, or technological changes. The Jacobs Foundation pursues this goal in two ways: by funding excellent research and through social interventions. Many of our operational partners in the Area of Social Intervention focus on the development of life skills, such as self-confidence, leadership, self-efficacy, decision-making, responsibility, in children and youth. Many times, our operational partners find it difficult to clearly understand, define, track and measure the development of life skills in their projects, particularly in settings where learning is less formal.The first volume of these guidelines aims to provide a better understanding of what we mean by life skills and why we think they are of such importance for children and youth development, as well as a hands-on practical guideline for our operational partners about how to monitor and evaluate the development and acquisition of life skills. The second volume aims to provide a tool box for monitoring and evaluating life skills in the field.