AC4 - The Book of Marvelous Magic is a 76 page book by Frank Mentzer and Gary Gygax published in 1985 by TSR, Inc. It is an accessory to Dungeons & Dragons primarily for use with the non-advanced box set versions; an appendix describes how the items described can be used with the AD&D game. The book's cover art is by Clyde Caldwell with interior art by Doug Watson, it has TSR item code TSR 9116 and ISBN 0-88038-192-2.
The Book of Marvelous Magic is the sourcebook on magical items and their twists and quirks. As well as all the miscellaneous magical items that appeared in the D&D Basic, Expert, and Companion Sets, over 500 new magical items are described in detail. Each item comes with a brief description and an explanation of its powers. The items are listed in alphabetical order by type of item. For example, under Blanket can be found the Blanket of Devouring, the Blanket of Protection, and the Blanket of Sleeping.
Chime of Visitors This simple metal stick is 3 inches long and made of a silvery metal. It keeps time as a chime of time but with an unusual side effect. If it rings while within 60 feet of any ordinary or otherwise known door, all creatures hearing the chime must make a saving throw vs. spells; all victims who fail the throw must go to the nearest door and open it or attempt to do so for at least six rounds.