%  Default values for the \preface markup
\prefaceformat{%
   \titleformat{\dumpinsertseject
                \centerline{\twelvept\bd\prefacetitle}
                \vs{1\bl}
                \setsubheadanumber{0}
                \setsubheadbnumber{0}
                \setsubheadcnumber{0}
                \setsubheaddnumber{0}
                }% end titleformat
  \incontents{yes}
}% end preface format