The Concrete Roman fonts were designed by Don Knuth for a book called "Concrete Mathematics", which he wrote with Graham and Patashnik (the Patashnik, of BibTeX fame). Knuth only designed text fonts, since the book used the Euler fonts for mathematics. The book was typeset using Plain TeX, of course, with additional macros that may be viewed in a file gkpmac.tex, which is available on CTAN.
The packages beton, concmath, and
ccfonts are LaTeX packages that change the default text
fonts from Computer Modern to Concrete. Packages beton and
ccfonts also slightly increase the default value of
\baselineskip to account for the rather heavier weight of the
Concrete fonts. If you wish to use the Euler fonts for
mathematics, as Knuth did, there's the euler package which
has been developed from Knuth's own Plain TeX-based set: these
macros are currently deprecated (they clash with many things, include
the AMSLaTeX). The independently-developed eulervm
bundle is therefore preferred to the euler package. (Note
that installing the eulervm bundle involves installing a
series of virtual fonts. While most modern distributions seem to have
the requisite files installed by default, you may find you have to
install them. If so, see the file readme in the
eulervm distribution.)
A few years after Knuth's original design, Ulrik Vieth designed the Concrete Math fonts. Packages concmath, and ccfonts also change the default math fonts from Computer Modern to Concrete and use the Concrete versions of the AMS fonts (this last behaviour is optional in the case of the concmath package).
There are no bold Concrete fonts, but it is generally accepted that
the Computer Modern Sans Serif demibold condensed fonts are an
adequate substitute. If you are using concmath or
ccfonts and you want to follow this suggestion, then use the
package with boldsans class option (in spite of the fact
that the concmath documentation calls it
sansbold class option). If you are using beton,
add
to the preamble of your document.\renewcommand{\bfdefault}{sbc}
Type 1 versions of the fonts are available. For the OT1 encoding, they are available from MicroPress. The CM-Super fonts contain Type 1 versions of the Concrete fonts in the T1 encoding.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=concrete