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The generic part is obviously minimal, but it could have been more accurate: it mentions that syntax and availability vary by implementation, but never attempts to classify which implements which. Not even the distinction between BRE and ERE. Character representations described in pages 5-13 are good for a lecture on "most available types of regular expressions": a rather vague concept.

By comparison, Perl Pocket Reference's chapter on regex is both more concise and more accurate than
Regular Expression Pocket Reference's chapter on Perl. However, the latter features a discussion on operators for regex and some examples that may make it clearer than the former. A complete example, using perl's command line options -i, -p, and -e, is missing.

There are repetitions, e.g. tables 26-30 for PCRE are reprinted exactly alike, except for different page breaks, as tables 31-35 for PHP's perl-compatible regex.

Emacs is missing. Is it less popular than vi?