\documentclass[a4paper, twoside]{book}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\input{chapters/preamble}
\newcommand{\mytitle}{My Thesis}
\title{\mytitle} %->->->->-> Check hyperref title <-<-<-<-<-
\author{Author's \textsc{Name}}
%\loadglsentries{chapters/glossary}
\begin{document}
\frontmatter
\pagestyle{empty}
\input{chapters/titlepage}
\input{chapters/coversheet}
\listoftodos
\input{chapters/epigraph}
\tableofcontents \pagestyle{fancy} \markboth{Contents}{Contents}
\input{chapters/chapter0}
\mainmatter
\fancyhead[RE,LO]{\thesection} % Custom header text
\input{chapters/chapter1}
\newcounter{auxiliary}
\setcounter{auxiliary}{\arabic{section}}
\appendix
\setcounter{section}{\arabic{auxiliary}} %The auxiliary counter solves the issue of section number-skipping in the appendices
%\glsaddall[types={definition}]
%\printnoidxglossary[sort=letter]
%\printnoidxglossary[sort=letter, type=definition]
%\printindex \markboth{Índice Remissivo}{Índice Remissivo}
\backmatter
%\nocite{*}
\FloatBarrier
\printbibliography[heading=bibintoc]
\end{document}
