Adapting tools recently developed in general linguistics and dwelling on a solid corpus study, this book offers the first comprehensive view on Classical Greek wh-clauses since Monteil (1963) and scrutinizes how wh-items (??, ?st??, t??) distribute across the different clause types. False ideas are discarded (e.g., there are no t?? relative clauses, ?st?? does not take over ??' functions). This essay furthermore teases apart actual neutralization and so-far-unknown subtle distinctions. Who knew that ?st?? is featured in three different types of appositive clauses? In the interrogative domain, an analysis is given of what licenses ?? to pop in and t?? to pop out. Tackling these topics and more, this essay draws a coherent picture of the wh-clause system, whose basis is the notion of (non)identification.