5.2 How can I get bold and italic fonts to work?

Emacs will only use the italic (and bold) versions of a font automatically if it has the same width as the normal version. Many fonts have italic and bold versions that are slightly wider. It will also only use real bold and italic fonts by default, where other applications may use synthesized variations that are derived from the normal font. To enable more italic and bold fonts to be displayed, you can enable synthesized fonts and manually set the font for italic, bold and bold-italic as follows:

(setq w32-enable-synthesized-fonts t)
(set-face-font 'italic "-*-Courier New-normal-i-*-*-11-*-*-*-c-*-iso8859-1")
(set-face-font 'bold-italic "-*-Courier New-bold-i-*-*-11-*-*-*-c-*-iso8859-1")

The w32-enable-synthesized-fonts variable is obsolete starting from Emacs 24.4, as Emacs no longer has this limitation.