Informal employment can be defined as 'the paid production and sale of goods and services that are unregistered by, or hidden from, the state for tax, social security and/or labour law purposes but which are legal in all other respects' (Williams and Windebank, 1998: 4). It is now recognised that informal employment is growing in importance as economies develop. This recognition that informal employment is far from some vestige of a pre-capitalist past that is peripheral and dwindling, but is a strong and growing part of advanced economies, has resulted in recent years in a growing interest in such work from both academics and public policy-makers. This special issue contains cutting-edge papers that deal with: measuring the changing size of this sphere; understanding the contemporary character of informal employment; and finally, what needs to be done about such work. These papers not only provide the reader with key insights into the nature of contemporary research on informal employment but also advance the study of informal employment in significant ways.