XFree86 comes with extensive documentation in the form of manual
pages and typeset documents. Before installing fonts, you really should
read the fontconfig(3) and
mkfontdir(1) manual pages; other
manual pages of interest include X(7),
Xserver(1), xset(1), Xft(3), xlsfonts(1) and showfont(1). In addition, you may want to read the X Logical
Font Description document, by Jim Flowers, which is provided in the file
`xc/doc/xlfd.PS.Z'.
The latest released version of the XFree86 documentation (including this document and all manual pages) is available as current XFree86 documentation.
The comp.fonts FAQ, which is unfortunately no longer being maintained, contains a wealth of information about digital fonts.
Xft and Fontconfig are described on Keith Packard's Fontconfig site.
The
xfsft home page
has been superseded by this document, and is now obsolete; you may
however still find some of the information that it contains useful.
Joerg Pommnitz' xfsft page
is the canonical source for the `ttmkfdir' utility, which is the
ancestor of mkfontscale.
The author's software pages might or might not contain related scribbles and development versions of software.
The documentation of X-TrueType is available from the After X-TT Project page.
A number of East-Asian CIDFonts are available from O'Reilly's FTP site.
While the Unicode consortium site may be of interest, you are more likely to find what you need in Markus Kuhn's UTF-8 and Unicode FAQ.
The IANA RFC documents, available from a number of sites throughout the world, often provide interesting information about character set issues; see for example RFC 373.