This book is here to help you get your job done. In general, you can use the code in this book in your programs and documentation (all the code is available for download in a zip archive from http://examples.oreilly.com/pdfhks/; most of the hacks assume these example files are in place in a working directory). You do not need to contact us for permission unless you're reproducing a significant portion of the code. For example, writing a program that uses several chunks of code from this book does not require permission. However, selling or distributing a CD-ROM of examples from this book does require permission. Answering a question by citing this book and quoting an example does not require permission, but incorporating a significant number of examples from this book into your product's documentation does require permission.
We appreciate, but do not require, attribution when using code. An attribution usually includes the title, author, publisher, and ISBN. For example: "PDF Hacks by Sid Steward. Copyright 2004 O'Reilly Media, Inc., 0-596-00655-1."
If you feel your use of code examples falls outside fair use or the permission given here, feel free to contact us at email@example.com.