This open access book tells the story of eight youth service organizations in the USA, using the voices of the impacted youth and the staff who accompanied them. Drawing on a series of structured interviews with young people and staff and informed by positive youth development (PYD), ideas the author proposes nine universal principles for working with youth from under-resourced neighborhoods that can be applied to any youth organization. The principles include orienting youth towards a purposeful future, providing an opportunity to build academic and critical thinking abilities, and developing individual's identity and sense of agency. The book contributes to the emerging methodology of principles-focused evaluation and draws on range of disciplines including psychology, education and youth studies. The ebook editions of this book are available open access under a CC BY-NC-ND 4.0 licence on bloomsburycollections.com. Open access was funded by the Thrive Foundation.