+ $q = new ZOOM::Query::CQL("creator=pike and subject=unix");
+ $rs = $conn->search($q);
+ $q->destroy();
+
+C<ZOOM::Query> is a virtual base class from which various concrete
+subclasses can be derived. Different subclasses implement different
+types of query. The sole purpose of a Query object is to be used in a
+C<search()> on a Connection; because PQF is such a common special
+case, the shortcut Connection method C<search_pqf()> is provided.
+
+The following Query subclasses are provided, both of the providing the
+same set of methods described below:
+
+=over 4
+
+=item ZOOM::Query::PQF
+
+Implements Prefix Query Format (PQF), also sometimes known as Prefix
+Query Notation (PQN). This esoteric but rigorous and expressive
+format is described in the YAZ Manual at
+http://indexdata.com/yaz/doc/tools.tkl#PQF
+
+=item ZOOM::Query::CQL
+
+Implements the Common Query Language (CQL) of SRU, the Search/Retrieve
+URL. CQL is a much friendlier notation than PQF, using a simple infix
+notation. The queries are passed ``as is'' to the server rather than
+being compiled into a Z39.50 Type-1 query, so only CQL-compliant
+servers can support such querier. CQL is described at
+http://www.loc.gov/standards/sru/cql/
+and in a slight out-of-date but nevertheless useful tutorial at
+http://zing.z3950.org/cql/intro.html
+
+=back
+
+=head3 Methods
+
+=head4 new()
+
+Creates a new query object,
+
+=head4 sortby()
+