This appendix is a catalog of the patterns that are discussed in the book. No new information is to be found here; instead, this is intended to be a service to the reader. You'll find here the source of the pattern where you can read more, a very condensed description, and most often a URL where you can instantly get more information.
You find this appendix online as well if you would like it to be clickable: www.jnsk.se/adddp/patterns
When the description is written between quotation marks, that means that the description is taken directly from the provided URL (or from the mentioned book's inner cover in the case of some of the [GoF Design Patterns]).