\documentclass{{article}}
\usepackage[papersize={paper_size}]{{geometry}}
\usepackage{{pdfpages}}
\begin{{document}}

\includepdf[pages=-]{{front-cover.pdf}}
\includepdf[pages=-]{{preface.pdf}}
\includepdf[pages=-]{{music.pdf}}
\includepdf[pages=-]{{back-cover.pdf}}

\end{{document}}