%------------ BOOKSTYLE ---------------
% see english.tex and francais.tex for messages
% \def\bookstylemessage{ <<< BOOK STYLE >>> } see English/French titles
\def\bookstyle{ \message {\bookstylemessage }
                 \documentstyle{\numberbychapter
                  \vheadersize = 1cm
                  \vfootersize = 2cm %this is set but not used can be
                  \vpapersize=23cm
                  \vouterpagesize=20cm
                  \hpapersize =8.5in
                  \houterpagesize=12cm
                  \leftmarginsize = 4.8cm
                  \topmarginsize = 3cm
                  \chaptername = {}
                  \def\chapterstartform{\ifodd\pageno\relax\else
                                         \line{}\ejectpage\fi\titlepagestyle}
                  \let\headermark=\topmark
                  \def\headermark##1{\global\let\headermark = ##1}
                  \headertext{\ifodd\pageno\rightheadertext
                                         \else\leftheadertext\fi}
                  \let\specialheadertext=\headertext
                  \def\rightheadertext{\line{\hss
                     \headermark\rlap{\ssheadfont\qquad\folio}}}
                  \def\leftheadertext{\line{\llap{\ssheadfont\folio
                                 \qquad}\the\chaptername\hss}}
                 \footertext{}  \specialfootertext={}
                 \normalheaderstyle
                 \blankfooterstyle
                 \everyprelude = {
                    \def\leftheadertext{\line{\llap{\folio\qquad}\firstmark}}
                    \def\rightheadertext{\line{\firstmark\rlap{\qquad\folio}}}
                    \specialheadertext{\ifodd\pageno
                                     \line{\hss\rlap{\qquad\folio}}      
                                     \else\line{\llap{\folio\qquad}\hss}\fi}}
                   }}

\bookstyle