Although implicit within the notion of the 'digital divide' there have been surprisingly few empirical studies of those who make little or no use of information and communications technology (ICT). In particular, we have only a partial understanding of the social circumstances and detailed social patterning of the non-uptake and non-use of new technologies such as computers and the Internet. Are non-users of these technologies, as is widely assumed, falling into existing and deep-rooted patterns of social and economic inequalities? What are the individual motivations and consequences of not using ICT in the contemporary 'information society'? Based on household survey data collected from a systematic sample of 1001 adults in England and Wales alongside follow-up in-depth interviews with 100 of these respondents, this paper seeks to develop a detailed conceptual understanding of people's non-use of computers. Firstly, it explores in detail which individuals may be excluded from computer use to varying degrees. Secondly, it considers why these individuals are not using computers in their day-to-day lives. In doing so the paper identifies a hierarchy of non-use of ICT - highlighting the recurring structured nature of this non-engagement but also recognising the agency of individuals in not making use of technologies which may have a limited relevance, utility or even pleasure in the context of their everyday lives.