Second edition, published July 2002.
(See the catalog page for this book.)
This bonus book is in Adobe PDF format. It is searchable from within the Adobe Reader, but not as a part of the overall Perl CD Bookshelf html collection.
The author maintains a website for this book at www.regex.info, which contains regular expression links, some code snippets from the book, a searchable index, errata, and more.
Go to Mastering Regular Expressions