RE: emacs vs. perl => regular expressions

[Drew Adams]

    I just got "Regular Expressions Recipes" by Nathan A. Good.
    I'm hoping to use it to learn RE. The book focuses on using
    Perl, vim, python and PHP. I would find it helpful if I could
    be pointed to documentation that outlines the unique RE features
    of emacs (or Xemacs).
    That way I could do the exercises in emacs also. I think that
    would be very helpful in learning RE for emacs.
    Is such documentation available? Any suggestions?

The _best_ book on regexes, with extensive comparisons between Perl, Emacs,
and other regex flavors: http://www.oreilly.com/catalog/regex/. - Drew