The chapter begins by offering a brief history of the industrial development debate since Smith’s time and motivates why the approaches to such development are categorised under the two types of DoL found in his WN for discussion. With extremely simplified portrayal of technologies, DoLfg analysis focuses on the production of final goods and their trade between countries. It is the basis for mainstream (neoclassical) trade and commercial-policy theories. Market failures are compartmentalised for dissection, enabling policy instruments for correcting each to be rank-ordered. DoLop portrays how production is divided into operations and processes, with complementarities woven into numerous systems of production (SPs) that crisscross at the firm, industry or national/regional/global economy levels. International economic integration has precipitated a South–North divide, as reflected in structural differences in the countries’ SPs. Arguments could be made that broad-based IPs are warranted to transform the Southern countries’ SPs to facilitate interactive learning that spurs development. Outlines for the ensuing chapters indicate how the major IP stances could accordingly be grouped.