Manufacturing industry is a crucial ingredient in national economic development. This is because of the value which is added to natural resources and intermediate products through industrial processing. Where this value is retained in an economy, its circulation can sustain many more jobs than are created directly in manufacturing itself. Even in so-called 'post-industrial economies', rising industrial output continues to be a key source of wealth creation despite rapidly contracting employment in manufacturing industry per se. The extraordinarily high rate of economic growth which Ireland experienced in the 1990s was largely driven by rapid expansion of its manufacturing sector, arising principally from a surge of inward investment by transnational firms which began around 1993. This chapter outlines the historical background to this recent phase of strong industrial growth, before examining in some depth the key dimensions of this crucial feature of the so-called 'Celtic Tiger' economy. The chapter concludes with an assessment of the long-term developmental implications of the form recent industrial development has taken, particularly in the light of certain weaknesses in the industrial structure which have become apparent in the early 2000s. Case studies of the microcomputer and pharmaceutical sectors are presented to illustrate key themes raised in the main text. The spatial dimensions associated with successive industrial development phases are also described and analysed.