At least since Socrates, philosophy has been understood as the desire for acquiring a special kind of knowledge, namely wisdom, a kind of knowledge that human beings ordinarily do not possess. According to ancient thinkers this desire may result from a variety of causes: wonder or astonishment, the bothersome or even painful realization that one lacks wisdom, or encountering certain hard perplexities or aporiai. As a result of this basic understanding of philosophy, Greek thinkers tended to regard philosophy as an activity of inquiry (zētēsis) rather than as a specific discipline. Discussions concerning the right manner of engaging in philosophical inquiry -what methodoi or routes of inquiry were best suited to lead one to wisdom -became an integral part of ancient philosophy, as did the question how such manners or modes of inquiry are related to, and differ from, other types of inquiry, for instance medical or mathematical.In this special issue of History of Philosophy & Logical Analysis, we wish to concentrate in particular on ancient modes of inquiry. 1 But, the reader may wonder, why do we talk about modes of inquiry, rather than methods? There are at least two reasons for this. First, the modern term 'method' gives connotations of something wider than inquiry: we talk of various methods for doing something, or for going about something, without thereby implying that we are directly engaged in inquiry into something. In another sense, however, method is narrower than inquiry; for a method proper prescribes in a strongly regulative way how to proceed in order to get from an initial state to another state. Whether there are any such prescriptions for philosophical inquiry is an open question, both now and in antiquity. Most ancient philosophers would agree, however, that there are, as it were, small-scale methods or techniques in philosophy, for instance the method or technique of disproving a claim by counterexample; and they would further agree that such methods play some role in inquiry. However, most real philosophical inquiries are far too complex to be carried out by relying on only one such method or technique. A proper method of philosophical inquiry would thus at least require a description of how these specific individual techniques can be combined. But even if no such largescale method can be discovered in philosophy, philosophical inquiry may still be possible and facilitated by certain modes or elements in a general account of such inquiry. This latter possibility is especially important for the sceptical school of the Pyrrhonists, who were keen on claiming that they were engaged in inquiry without subscribing to any of the various methodoi which had been developed up to this point, and, in fact, to any specific method of inquiry at all. It 1 In the past years, a number of seminal contributions in relation to inquiry in ancient philosophy have been published; see, for instance, Fine (2014), Politis (2015) or Karamanolis & Politis (2018).