The concept of ‘real legal certainty’ provides a much needed corrective to the general attention for legal certainty in this day and age. It emphasises relations between citizens, adds socio-legal insight, provides a ‘view from below,’ and thus leads to more realistic insights on how to build state institutions. The concept was introduced by Leiden University’s professor of Law and Governance in Developing countries Jan Michiel Otto, and can be considered a central pillar of his work. Against the backdrop of an ever-increasing interest in ‘legal certainty’ in policy-making and academia, friends and colleagues of Jan Michiel Otto engage with the concept provide a wide variety of examples of its relevance. Drawing on case material from all over the world, they show how real legal certainty can be understood in a bottom-up manner and how it is relevant for building state institutions. They also show how the concept can gain in relevance by taking into account actors other than the state. In all, the edited volume is important reading for all whom share professor Otto’s interest in what it takes to bridge law in the books and law in action.