This book presents a compelling, science-based guide for navigating life's many transitions: from first jobs to midlife pivots to purposeful retirements. Based on insights from over 1000 people across all ages and career stages, it blends identity work, prototyping, and psychological capital to foster sustainable, purpose-driven career paths. Drawing on design thinking, positive psychology, and behavioral science, each chapter encourages reflection, exploration, and growth, supported by a practical toolkit featuring methods such as the Magic Circle, Life Loops, and the Stairway to Heaven. Readers are equipped to overcome procrastination, redesign habits, explore bold dreams, and build a portfolio life that reflects personal evolution. Whether you're feeling stuck, restless, or ready for something new, Design Your Future will help you take action with confidence and joy. This book is not about making the perfect plan; it's about designing your next brave step.