Life doesn't come with instructions.
Fortunately, death is different.
When Adam and Barbara die, they come back to their house to find some strange things are happening. Among them is the appearance of a rather odd book:
ADAM: "Handbook for the Recently Diseased"
BARBARA: I don't know where it came from. Look at that publisher.
ADAM: "Handbook for the Recently Deceased Press."
BARBARA: You know what? I don't think we survived the crash.
Yeah, this book is sort of a dead give away. Get it? Oh, we slay ourselves. Get that?
So, what is The Handbook for the Recently Deceased? It's basically a guidebook for newly dead folks to answer their questions about the afterlife. As Adam and Barbara quickly find out, it reads like "stereo instructions." This is late-'80s speak for "it's tough to understand and probably written in a foreign country." Back then, the instruction manuals that came with stereo systems had a reputation for being super complicated.
That's the genius of IKEA. No words. Just sayin'.
The Handbook does come in handy a few times. It explains to the Maitlands why no one can see them (but why Lydia can). The book also tells Adam that he can get help by drawing a door and knocking three times. Plus, there's the intermediate interface chapter on haunting. So it's not totally useless.
Of course, in the wrong hands, The Handbook can be used for evil ends. Once Otho snags it from the attic, he's able to use it for a séance that summons the Maitlands back into their bodies and starts to exorcise them. You've gotta wonder why the publishers decided to include that little nugget in The Handbook for the Recently Deceased. Maybe it was in the chapter titled "Don't Try This at Home."