The book "Start Up of You" by Reid Hoffman is about how to adapt, take risks, grow your network, and transform your career in today's rapidly changing professional landscape. It provides strategies and insights on how to navigate the challenges of the modern job market and build a successful and fulfilling career. The book emphasizes the importance of treating your career as a startup, constantly evolving and adapting to new opportunities and challenges. It also highlights the significance of building a strong professional network and leveraging it to create new opportunities. Overall, "Start Up of You" offers practical advice and actionable steps to help individuals thrive in their careers.