Policy makers at local, devolved and central government levels in the UK are much involved in the expansion of early intervention for children in both specialist targeted and mainstream services. They place much faith and anticipation in the notion of engaging early in the needs of children and young people and while this paper endorses the ambitions of early intervention, it asks how well placed are those sentiments that assume a relatively uncomplicated and positive role for such an approach. The paper addresses some key conceptual and practical features of early intervention services and explores a number of challenging themes that are likely to impede effective delivery. The themes are broadly outlined in order to include a number of critical perspectives that bear upon policy, practice and research in this field and which, together, summarize a contested realm in which global, cultural, organizational, resource, systemic and evaluative issues will in large part inform the design of early intervention and our understanding of its intended benefits. The paper concludes with commentary on the broad state of play in what we know about early intervention and identifies some key areas for future research.