Despite a voluminous ‘lessons learned’ literature, there is much that we do not understand about rule of law assistance. Conceptually it lacks clarity and in practice seems to proceed in the absence of rigorous empirical research and ‘thick’ descriptions of the institutional histories, reform politics and the legal and social cultures of the countries it targets. Many academic colleagues, development practitioners, lawyers and policy-makersand students are troubled by the knowledge vacuum in rule of law assistance. Here I consider some of the genuine and persistent questions about its scope and effect. I suggest that we need to find better answers, for our own intellectual and practical purposes, but also for the citizens of developing and transitional economies, who are the intended ‘beneficiaries’ of much rule of law assistance.