From the PDF introduction
A Web Enhancement for the Book of Challenges
When getting ready to face the encounters in the Book of Challenges, or any other venture underground, your chances for success (and survival) will improve if you’re prepared to assess the Dungeon Environment properly. All too often, players concentrate on their characters’ combat abilities and neglect equipment that serves other purposes.
This web enhancement suggests some magic and equipment that player characters (PCs) might overlook before entering a challenging dungeon. This bonus material is exclusive to the official DUNGEONS & DRAGONS® website.