This chapter is an historical perspective on the internal market. It is a challenging enterprise. To distil a narrative flow from 60 years of development necessitates discretion and choice, the very exercise of which perforce shapes the ensuing story. There are doubtless multiple stories that could be told. I have ‘form’ in this respect, having already had one shot at this twenty years ago, when I articulated a relatively straightforward linear trajectory. This chapter is not, however, an updated version of that penned earlier. It is a different view of the cathedral, which is more accurately regarded as historical-conceptual. The narrative consists of three distinct, albeit related, parts. The first part is concerned with negative integration and the four freedoms, and is dealt with in sections II-VI. The analysis begins by setting out the conceptual frame that is used to explore the four freedoms. It draws on Robert Schutze’s three models of integration, the international, the federal and the national, as the lens through which to view the development of the law in the respective areas. It will be argued that the contours of the internal market have been shaped principally by the interplay between the international and federal models; that the balance between the two is not identical across all four freedoms; and that there are interesting differences in the meaning of discrimination and market impediment that underpin the two models when applied in relation to the four freedoms. The focus in the second part of the chapter switches to positive integration and harmonization, which is examined in sections VII-IX. It begins by setting out the classic story of positive integration, which has a Treaty dimension, a legislative dimension and a judicial dimension. There is much in this that withstands scrutiny. It will, nonetheless, be argued that the received wisdom concerning the critique of Article 114 is misplaced in certain respects, when analysed from a constitutional, interpretive and political perspective. It will also be argued that there is excessive concentration on Article 114 TFEU when considering positive integration in the EU. The internal market has been advanced by many regulations and directives enacted pursuant to other Treaty provisions. Some entail harmonization, others do not. It should not, however, be assumed that harmonizing measures are necessarily more efficacious, or more limiting of Member State autonomy, than other legislative provisions designed to advance the internal market. There is, as will be seen, no a priori reason why this should be so. The final part of the chapter considers the tension between the economic and the social in the internal market, which is addressed in section X. The nature of the tension is set out, including the implications for the EU legal order. This is followed by discussion of the ways in which the tension is alleviated, albeit not cured. The factors that are salient in this regard are constitutional architecture, Treaty amendment, judicial interpretation, and the changing conception of the internal market.