Despite the fact that talk of anonymity abounds in the twenty-first century (“anonymous sources,” “anonymity promises,” “anonymity guarantees,”), anonymity as a concept has thus far flown very low on the philosophical radar. Those who do write about anonymity do so with either secondary importance, as a way to analyze some other more fundamental value or as a preamble to an analysis of the importance of anonymity in a particular applied context (e.g. the anonymity of whistleblowing). My goal in this paper is not to provide a positive articulation of the concept of anonymity (though I think one is possible) or, to go beyond that, and assess its value. Rather, my aim is to make a start on these bigger projects by, more modestly, determining whether a distinct and coherent concept of anonymity is possible. My particular focus is the view of those I call ‘reductionists,’ who aim to reduce anonymity to other concepts of which we already have thoroughgoing analyses and which may better capture the values we are seeking: privacy, liberty and autonomy, security and protection, and secrecy. I argue that, while anonymity features prominently in our understanding of these related values, there is good reason to resist the reductionist view.