The recent international surge in private equity markets has been accompanied by growing interest in its nature and effects. Private equity involves investment in unquoted companies and includes both early stage venture capital and later stage buyouts. The latter, which have been particularly controversial, are our focus. This paper provides a review of the different theoretical approaches that have been deployed to understand this phenomenon. Thereafter, the findings of a large cross section of empirical studies within a range of different national settings are compared and contrasted. Finally, existing themes emerging from – and gaps in – the existing literature and likely future directions are summarized.