Chapter style like this without memoir?

Question

I was looking for style inspiration for my thesis and I came across this chapter style:

As far as I am concerned memoir class is capable of this kind of typography like specified in Bringhurst chapter style in memoir, but I am trying to produce it using the book class. I would be grateful if someone in here can share his/her knowledge about the code used to produce this style.

Answer 1

Here's some possibility using the titlesec package and a font admitting large sizes; adjust the settings according to your needs:

\documentclass{book}
\usepackage[explicit]{titlesec}
\usepackage{lmodern}
\usepackage{lipsum}

\newlength\chapnumb
\setlength\chapnumb{4cm}

\titleformat{\chapter}[block]
{\normalfont\sffamily}{}{0pt}
{\parbox[b]{\chapnumb}{%
   \fontsize{120}{110}\selectfont\thechapter}%
  \parbox[b]{\dimexpr\textwidth-\chapnumb\relax}{%
    \raggedleft%
    \hfill{\LARGE#1}\\
    \rule{\dimexpr\textwidth-\chapnumb\relax}{0.4pt}}}
\titleformat{name=\chapter,numberless}[block]
{\normalfont\sffamily}{}{0pt}
{\parbox[b]{\chapnumb}{%
   \mbox{}}%
  \parbox[b]{\dimexpr\textwidth-\chapnumb\relax}{%
    \raggedleft%
    \hfill{\LARGE#1}\\
    \rule{\dimexpr\textwidth-\chapnumb\relax}{0.4pt}}}

\begin{document}

\chapter*{A Long Title for an Unnumbered Test Chapter}
\lipsum[4]
\chapter{Introduction}
\lipsum[4]

\end{document}

An image for an unnumbered (starred) chapter:

An image for a numbered chapter: