DeepTech entrepreneurs are tremendously important for our society and economy. This playbook is a framework to master the complexity of DeepTech ventures. It is practical and the result of hard-earned lessons of what has and what hasn't worked in the past. It introduces business readiness levels that help focus and guide execution. It enables system-thinking that aligns customer-centric product management, technology development, industrialisation, commercialisation, and strategic decision-making. It provides a definition of product-market fit and a framework for how to find it. It encourages agile, hypothesis-based decision-making and the frontloading of risks. It provides a substantial terminology chapter to avoid communication errors and misunderstandings. If this playbook helps to bridge the gap between invention and commercial success, it will contribute to reducing the risk for DeepTech entrepreneurs while maximising return on investment.