This book furnishes a rich description and discussion on the theory and practice of DPYD (digital positive youth development) games, in particular, design, implementation, and initial evaluation. Chapters show a concerted and creative effort in providing preventive measures on commonly found adolescent developmental issues. They also demonstrate that the newly developed and specially designed games are in general efficient and effective measures to promote youth development and prevent some common adolescent problems from deteriorating in contemporary urban societies. Initial users' qualitative feedback supports their effectiveness. Findings related to motivational variables such as self-efficacy, situational interest, goal orientation, and engagement variables are discussed. It is noteworthy that the game on interpersonal relationship has a special feature of promoting cross-cultural understanding of the values behind Chinese and Western (English-speaking only) cultures.