Introduction Informal employment is here defined as paid labour unregistered by or hidden from the state for tax, social security and labour law purposes (European Commission 2007). Akin to the other eight labour practices considered in this book, different varieties exist, ranging from waged informal employment where employees are employed on an undeclared basis by formal or informal businesses to informal self-employment which can be conducted by own-account workers who work either wholly or partially off-the-books. In this chapter, the intention is to evaluate the prevalence and nature of informal employment in post-Soviet/socialist spaces. To achieve this, first, a brief review is undertaken of the different methods of measuring informal employment and the varying estimates produced by such methods of the magnitude of informal employment in post-Soviet/socialist societies. Second, and so as to provide a richer and more textured understanding of how informal employment is embedded in daily life in post-Soviet societies, empirical evidence from Ukraine is reported, followed in the third section by evidence from Moscow. This will reveal not only the multifarious forms of informal employment in postSoviet societies, but also how informal employment is not a distinct category but merges into the other forms of labour considered in other chapters. At the outset, however, it is necessary to be clear what is being discussed in this chapter. Despite being variously referred to by 45 adjectives, such as ‘cash-in-hand’, ‘informal’, ‘black’, ‘underground’, ‘hidden’ and ‘shadow’ and 12 nouns including work, employment, economy and sector (Williams 2004a), there is a strong consensus regarding the types of endeavour included and excluded when discussing this form of work. Informal employment is widely accepted as involving only the production and sale of goods and services that are licit in all respects besides the fact that they are unregistered by or hidden from the state for tax, benefit and/or labour law purposes (European Commission 1998; Feige 1999; Portes 1994; Renooy et al. 2004; Thomas 1992; Williams 2006a; Williams and Windebank 1998). When the goods and services provided are illicit (e.g. drugtrafficking), such endeavour is excluded, as are non-cash exchanges and subsistence production that is not exchanged. Blurred edges, nevertheless, do remain.