The thesis investigates the phenomenon of pied-piping (see Ross 1967). It is argued that pied-piping is less idiosyncratic and construction-specific as is often assumed. Five properties of pied-piping are identified and it is argued that these hold across a number of different languages and different constructions. The syntactic problem of pied-piping, which emerges from the general assumption that only [wh]-marked constituents should be able to undergo [wh]-movement, is addressed without making reference to the notion of feature percolation, a concept which is argued to be both empirically and conceptually problematic.

The five properties of pied-piping are expressed by five generalizations. The first three of these generalizations are concerned with pied-piping as it appears in embedded questions and restrictive relative clauses. The last two generalizations address massive pied-piping (in the sense of Safir 1986) as it typically emerges in appositive relative clauses (and maybe also matrix questions). The generalizations capture (i) transitivity-effects in pied-piping, (ii) the phenomenon of wh-movement within the pied-piped constituent (internal wh-movement in the sense of van Riemsdijk 1985), (iii) the role of pied-piping as a repair-strategy, (iv) the emergence of massive pied-piping, and (v) intervention-environments that block massive pied-piping.

The derivation of these generalizations is embedded within a hybrid theory of grammar which contains both aspects of the phase-based theory of Chomsky (2001) and of an optimality theoretic grammar, (see Prince & Smolensky 2004). The core of the theory is formed by a constraint called Local Agree, which favors local applications of Chomsky's (2001) operation Agree over remote applications of Agree.

The leading idea is that on the one hand the non-local character of feature checking in the context of pied-piping can be accounted for by application of remote Agree and that on the other hand restrictions on pied-piping, which suggest that locality requirements play some role for pied-piping after all, can be captured best if (a) remote Agree is generally minimized and (b) sometimes even completely blocked. The implementation of (a) makes crucial use of the assumption that the constraint Local Agree is violable. The derivation of (b) is based on the notion of a phase (in the sense of Chomsky 2001) and its opaque character (expressed by Chomsky's PIC). Finally, for the case of massive pied-piping, which seems not to be subject to any locality requirements on Agree, it is argued that the gap in locality is bridged by application of the operation of [wh]-feature movement in the sense of Chomsky (1995).