| • Science | • People | • Locations | • Timeline |
Questions relating to the game were printed in the book. For example, "How can I kill the songbird?" An "empty" box was located below or following the text. The answer the box contained could only be made visible by using a special highlight-like marker pen that came with the book.
This marker pen contained a special solution that revealed the clue/hint. Over time, the "invisible" text would fade again.
Some books even contained maps and other supplements that aided in solving the games.
Though, like the games, InvisiClues, are no longer available, they are located on some Internet sites and with boxed collections of their games which Activision releases from time to time.
Infocom