This article gives a general overview of the main issues covered in the literature on the new economy. The latter is defined as an economy in which the emergence of a new production sector, that of the Information and Communications Technologies (ICT), affects the growth rate of productivity in a sustainable way. The article briefly outlines the sector's characteristics, and more specifically its weight within the main economies. Within the theoretical framework of growth accounting, it can be demonstrated that ICT can have an impact on labour productivity through three transmission channels: the ICT capital intensity; the total factor productivity (TFP) in the ICT-producing sector; and the TFP in the ICT-using sectors. Various empirical surveys have been recently conducted into the role of the new economy in the United States, which differs from most other countries in that it has overall achieved a faster development of ICT and recorded better macroeconomic performances throughout the nineties. They conclude that ICT account for most - if not all - of the acceleration of labour productivity growth which has been observed in this country between the first and the second half of the nineties, thanks to the contribution of the first two aforementioned transmission channels. The presence of the third channel, i.e. the diffusion to the whole economy of technical progress that is not embodied in the ICT capital goods, remains however a matter of controversy. The question of the technological shock's long-term sustainability is also dealt with. Special attention is given to certain theories based on vintage-capital models and Schumpeterian models, which offer an explanation both for the slowdown of productivity observed in the United States in the seventies and for its more or less recent acceleration. Finally, mutual relations between the new economy and economic policy are also discussed.