%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-3-21 on page I-347 in "paracol --- Several text streams aligned".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See
https://www.latex-project.org/lppl.txt for details.
%%
\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{183.0pt}
\setlength\parindent{0pt}
\setlength\marginparwidth{15pt}
\setlength\marginparsep{5pt}
\addtolength\textwidth{-2\marginparwidth} % make room on the page
\addtolength\textwidth{-2\marginparsep} % in the book example
%StartShownPreambleCommands
\usepackage{paracol} \marginparthreshold{2}
%StopShownPreambleCommands
\begin{document}
\begin{paracol}{3}
Left\marginpar{L1} \switchcolumn
Middle \\ Middle \\
Middle\marginpar{M2} \switchcolumn
Right \\ Right\marginpar{R3} \switchcolumn*
\marginparthreshold{1}
Left again\marginpar{L4} \switchcolumn
Middle\marginpar{M5}
\end{paracol}
\end{document}
