In this masterful monograph, Alice Rio revisits one of the central questions in the historiography of early medieval Western Europe: how did the transition from slavery to serfdom take place?While many earlier answers to this question have proposed a more or less linear trajectory from late Roman slavery to the serfdom of the central Middle Ages, Rio sets out a compelling and elegant argument for a rather less elegant state of affairs: instead of trying to contort the messy source base into a seamless theory, she sensibly and convincingly argues that 'there is a fundamental problem with looking for a single linear story here: the line is far too broken up, too frayed with little individual threads making their own bids for escape, and often leading nowhere ' (p.248).Rather than smoothing over the very wide range of variation in what unfreedom could mean in this period, Rio aims to provide an interpretation of that diversity that can explain an overall trajectory without seeking to pare off the divergent possibilities that the sources present us with.The first part of this book examines pathways into the condition of unfreedom, namely sale after being captured in war, self-sale, debt slavery, and penal enslavement; and ways out of that status through purchase and manumission.Rio next discusses the nature of two kinds of unfreedom: household slavery, and unfree status on large agricultural estates.Her last chapter provides an analysis of the legal and institutional framework for unfreedom, with a focus on the ways in which Church, state, and private lordships approached it through efforts to control marriage.In most of these chapters, Rio moves successively through different regions: Francia, Italy, the Iberian peninsula, Anglo-Saxon England, and Ireland, of which the first two tend to get the most coverage; in some chapters, Byzantium and the Slavic lands get a look in as well.In the introduction, she surveys some of the main landmarks of the debates on the issue of transition from slavery to serfdom, and sets out the main questions that drive her own analysis: why did the powerful seek to categorise some people as unfree, and not others, and what were the advantages that they felt accrued to them therefrom?And crucially -although this is less explicit in the introduction than in the following chapters -how and why did dependants themselves negotiate these categories, and what benefits could they have got not just from moving from being unfree to free, but also the other way round?My principal criticism of this book is worth stating at the outset, since it is a matter of terminology: is this a study of 'unfreedom' or 'slavery'?In Roman sources, servus means something that we can translate unambiguously as 'slave', but its connotations in medieval texts can range from 'slave' to 'serf', and even 'servant'.On a number of occasions, the choice between 'slavery' or 'unfreedom' is a matter of