> Is the TeXBook, chap. G now obsolete? No, app G explains how the math typesetting uses font parameters from the tfm files, but a tfm may have other font parameters that are notautomatically used by tex but may be extracted by the \fontdimen command. Th ec fonts (probably only these) have the extra parameters as described. TeX, itself doesn't use them but you may use the values in your tex code. David