%%
%% The LaTeX Companion, 3ed
%%
%% Example A-1-8 on page II-630 in "Defining simple environments".
%%
%% 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}
%StartShownPreambleCommands
\newenvironment{Abstract}
  {\begin{center}\normalfont\bfseries Abstract%
   \end{center}\begin{quote}}{\end{quote}\par}
%StopShownPreambleCommands

\begin{document}
\begin{Abstract}
 This abstract explains the approach used
 to solve the problems at hand.
\end{Abstract}
Some text following the abstract. Some text
following the abstract. And some more.
\end{document}