I want the chapter's author name being shown in the ToC. So I have modified the chapter to add the author there and use it in the page header as follows:
\documentclass[10pt,twoside]{memoir}
\usepackage[german]{babel}
\usepackage{blindtext}
\usepackage[ansinew]{inputenc}
\renewcommand{\thesection}{\arabic{section}}
\setcounter{secnumdepth}{3} % Subsection mit Zähler (1.1) versehen
%%
% Kolumnentitel
%%
\renewcommand{\chaptermark}[1]{ \markboth{#1}{} } % Stil der Kopfzeile zurücksetzen
\renewcommand{\sectionmark}[1]{ \markright{#1}{} } % Stil der Kopfzeile
% Page style
\makepagestyle{mystyle}
\makeevenhead{mystyle}{\thepage}{\small\chapterauthor}{}
\makeoddhead{mystyle}{}{\slshape\leftmark}{\thepage}
\pagestyle{mystyle}
%%
% Inhaltsverzeichnis
%%
\renewcommand*{\cftchapterdotsep}{\cftdotsep}
\settocdepth{chapter}
\renewcommand{\cftchapterfont}{\normalfont}
\renewcommand{\cftchapterpagefont}{\normalfont}
\makeatletter
\DeclareRobustCommand\authortoctext[1]{%
{\addvspace{10pt}\nopagebreak\leftskip0em\relax
\rightskip \@tocrmarg\relax
\noindent\itshape#1\par\addvspace{-7pt}}}
\makeatother
\newcommand\authortoc[1]{%
\gdef\chapterauthor{#1}%
\addtocontents{toc}{\authortoctext{#1}}}
%%
% Dokumentenbeginn
%%
\begin{document}
\tableofcontents*
\authortoc{Walter von der Vogelweide}
\chapter{Ich sass uf eynem Steine?}
\section{Und dachte Bein mit Beine}
\Blindtext\Blindtext\Blindtext\Blindtext
\authortoc{Hartman von Aue}
\chapter[Was auch immer]{So gebt nur mehr und immer mehr}
\section{Moralische Quellen der Irrationalitat}
\Blindtext\Blindtext\Blindtext\Blindtext
\end{document}
Everything works as expected, but I have the problem that sometimes author's name and chapter's title are split up by the page break. So that the first become an orphan and the latter a widow. How to avoid that?
needspacepackage and add a line\addtocontents{toc}{\needspace{2em}}%before\addtocontents{toc}{\authortoctext{#1}}}in the definition of\authortoc. – karlkoeller Sep 19 '13 at 06:00