I am working on a book right now and the margin notes are not appearing on the left-side pages. I tried using mparhack but it made no difference. Is my geometry, fancy style or another package messing up the normal layout? I am using pdflatex to render. Here is a minimal test case:
\documentclass[twoside,10pt]{book}
\usepackage[margin=9mm,paperwidth=107.95mm,paperheight=174.63mm,bottom=18mm]{geometry}
%\usepackage[cam,a4,center,pdftex]{crop}
\usepackage{lmodern}
\usepackage[T1]{fontenc}
\usepackage{fancyhdr}
\usepackage{lipsum}
\pagestyle{fancy}
\fancyhead{}
\fancyfoot[C]{\thepage}
\renewcommand{\headrulewidth}{0pt}
\fontsize{10.5}{13}\selectfont
\usepackage[sc,medium]{titlesec}
\usepackage{tocloft}
\addtocontents{toc}{%
\protect\renewcommand{\protect\cftchapleader}{%-- switch it on here
\protect\cftdotfill{\protect\cftdotsep}}}
\addtocontents{toc}{\protect\thispagestyle{empty}}
\renewcommand{\cfttoctitlefont}{\hfill\scshape}
\renewcommand\cftaftertoctitle{\hfill\null\\\null\hfill\scshape{Page}}
\renewcommand{\cftchapfont}{\normalsize\scshape}
\renewcommand{\cftchappagefont}{\normalsize\scshape}
\setlength{\emergencystretch}{3em}
\title{Heroic Real Estate Otter of the 21st Century}
\date{}
\begin{document}
\frenchspacing
\chapter*{Thread 0}
\addcontentsline{toc}{chapter}{Thread 0}
\pagestyle{fancy}
\hspace{0pt}\marginpar[$\omega$]{$\omega$}\lipsum[4-6]
NEXT\hspace{0pt}\marginpar[$\psi$]{$\psi$}\lipsum[10]
\end{document}
\hfill
in front of$\psi$
and you'll see it.