This chapter sets out the book’s structure and contributions. It argues for the distinct and important role of the Board of Trade in building the British regulatory state over a three-hundred year period from 1622 to 1914. Micro-economic governance was at the heart of regulatory state-building, showing deep continuities in the administrative legal basis of that regulation. The Board of Trade built on seventeenth-century traditions of the commissions, committees, and councils of trade of openness towards petitioning from merchants and business interests, and relationships between Board of Trade officials and merchants and business interests in market-shaping work illustrates the partnership in British state-building with non-state interests. The Board encapsulated the eighteenth century’s lack of integration of territorial officialdom in administering the colonies and empires. It was emblematic of the building of officialdom from a familial yet bureaucratic advisory core towards a centralised, extensive, and professionalised executive office of state. The Board of the nineteenth century was the fulcrum of the centralisation and integration of service officialdom over micro-economic regulation of infrastructure and companies. It was at the centre of outward-facing linkages with the domestic industrial and international financial-commercial sectors, and demonstrates the connections between British regulatory state-building, trade, and the maritime empire.