Out-of-school time (OST) settings are powerful contexts for youth development when programs and services are intentionally designed. "Youth Development Principles and Practices in Out-of-School Time Settings" increases the capacity of students and professionals to facilitate youths' optimal transition to adulthood through maximizing the developmental benefits accrued by participating in OST programs and experiences. Peter A. Witt and Linda L. Caldwell, two well-respected researchers in the youth development field, have brought together a group of outstanding authors who provide an exceptional blend of theory- and practice-based information critical to anyone seeking to conceptualize, design, and evaluate OST programs. All chapters are based on tenets of positive youth development necessary to enable youth to thrive. The book is divided into five sections: (1) Youth development principles and foundational information (e.g., youth today as well as an historical perspective on youth work); (2) Developing youths' potential (including specific chapters on leisure and recreation, youth sport, nature-based activities and the arts); (3) Systematic program planning and evaluation of youth programs; (4) The role of adults and families in the lives of youth; and (5) Issues of diversity in youth development (e.g., race and ethnicity, immigrant, LGBT, and ability level). A final chapter discusses the knowledge, skills, and behaviors necessary to become a skilled youth professional. Each chapter ends with thought-provoking discussion questions and assignments that encourage application and further exploration of the chapter's content. The book is a must read for students and practitioners seeking to understand youth today and support their development through out-of-school time programs. This book contains the following chapters: (1) Ten Principles of Youth Development (Linda L. Caldwell and Peter A. Witt); (2) The Big Picture: Youth Today and Tomorrow (Linda L. Caldwell); (3) Growing Up Slower With Fast-Forward and Like Buttons (Linda L. Caldwell); (4) It's a No-Brainer: Understanding the Adolescent Brain Is Important (Linda L. Caldwell and Elizabeth H. Weybright); (5) Why and How Youth Services Were Developed (Peter A. Witt); (6) Youth-Serving Organizations: Then and Now (Peter A. Witt); (7) Processes of Positive Development: Classic Theories (Reed W. Larson and Kathrin C. Walker); (8) Resiliency, Protective Processes, Promotion, and Community Youth Development (Daniel F. Perkins, Linda L. Caldwell, and Peter A. Witt); (9) The Importance of Leisure and Recreation as Contexts for Youth Development (Linda L. Caldwell and Peter A. Witt); (10) The Status of Youth Sport in American Society (Gareth J. Jones, Jason N. Bocarro, and Michael B. Edwards); (11) Nature and Youth Development (Barry A. Garst); (12) The Arts and Creative Youth Development (Denise Montgomery); (13) Intentional Programming Using Logic Models (Linda L. Caldwell, Peter A. Witt, and Cheryl K. Baldwin); (14) Program Assessment and Evaluation (Ann Gillard and Laurie Browne); (15) Reducing Attrition from Youth Programs Through Structuring Deep, Valued, and Impactful Experiences for Youth (Gary D. Ellis, Andrew Lacanienta, and Patti A. Freeman); (16) The Power of People: The Importance of Relationship-Based Programming (Jason N. Bocarro and Peter A. Witt); (17) Family Matters: Supporting Positive Youth Development through Family Programming (Karen K. Melton, Camilla J. Hodge, Nicole McAninch, and Ericka J. Olschewski); (18) Youth Engagement, Voice, and Opportunities for Decision-Making (Theresa K. Sullivan, Rebecca N. Saito, and Rachel Chamberlain); (19) The Role of Culture in Out-of-School Time Settings (Corliss Outley, Aishia Brown, M. Gayle Gabriel, and Alex Sullins); (20) Culturally Responsive Organized Activities: Lessons Learned from Latinx Families Living in the U.S. (Andrea Vest Ettekal and Sandra D. Simpkins); (21) Leisure and Recreational Sport Among Immigrant Youth (Monika Stodolska and Leslie N. Camarillo); (22) Out-of-School Time Programs and Resistance to LGBT Oppression (Daniel Theriault); (23) Including Youth of All Abilities (Lynn S. Anderson and Mary Ann Devine); and (24) So, You Want to be a Youth Professional (Peter A. Witt). (Individual chapters contain references.)