/documentclass{article}
/usepackage{pdfpages}
/begin{document}
/includepdfmerge{summary.pdf,-}
/includepdfmerge{me.pdf,-}
/includepdfmerge{expectations.pdf,-}
/end{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Note that we need to use "pdflatex" to compile to pdf directly.
It seems that many people have such questions. I googled and found many similar solutions but none of them work (maybe because of some setting). Last, I found this one (from http://cohomo.blogbus.com/logs/68109667.html), and it works!!!