While great effort is made to assure the accuracy of our texts, errors may still exist. If you find an error, please let us know by sending an e-mail to editor@parallax.com. We continually strive to improve all of our educational materials and documentation, and frequently revise our texts. Occasionally, an errata sheet with a list of known errors and corrections for a given text will be posted to our web site, www.parallax.com. Please check the individual product page's free downloads for an errata file.