Syntactic complexity has always been a matter of intense investigation in formal linguistics.
Since complex syntax is clearly evidenced by sentential embedding and since embedding of one
clause phrase in another is taken to signal recursivity of the grammar the capacity of
computing syntactic complexity is of central interest to the recent hypothesis that syntactic
recursion is the defining property of natural language. In the light of more recent claims
according to which complex syntax is not a universal property of all living languages the
issue of how to detect and define syntactic complexity has been revived with a combination of
classical and new arguments. This volume contains contributions about the formal complexity of
natural language about specific issues of clausal embedding and about syntactic complexity in
terms of grammar-external interfaces in the domain of language acquisition.
