Sounds inconvenient, though possibly better than not being able to go anywhere ever.

Next.

Negotiations.  This is another casual chapter; it's not immediately obvious why those weren't put next to each other.  There are suggested page numbers for untethering spells, for the most convenient possession spells for bribery (balancing being pleasant for the ghost against the comfort and safety of the host), for an exorcism spell that can be performed fast, for something to give a ghost a little zap of pain.

There are several pages of what appear to be completely mundane cooking recipes, with which to bribe possessors.

"Push and pull (carrot and stick, if you will) are both essential.  However, a light touch is required with negative motivation; spirits are much less stable than their living counterparts, as a rule, and it's quite easy to ruin a working relationship with only a little sharpness.  Often, all that is necessary is to remind the spirit that your support and continued presence relies upon his or her cooperation.  Gently, gently:  that's the way.

"But this fragility is also to your benefit—of course one may motivate ghosts with messages conveyed to living persons, or with sensory experiences, but even a little expressed sympathy, costless to you, can sometimes get you what you want.  The offer of a hug to a possessor about to leave his or her host has more than once been the act that convinced a spirit to work with me.  But perceived insincerity or aggression is intensely detrimental; use careful judgement."

She notes emphatically that work and entertainment should be kept separate, when it comes to ghost relations.  The spell on this page to put a ghost in more extended pain may be amusing to some, "but even those who find joy in these things should really know better than to sling it out on a spirit from whom they want something.  It does not help.  Only fools do this."

(Though she does mention that she suspects that if both you and the ghost believe in free love, this could be useful on both the sensory-bribery and social fronts.  She has not personally tried it although she knows of spellcasters who have; it seemed to work pretty well for them although you have to be mindful of keeping your hosts cooperative, if you don't have lots of options handy.)

There's also a warning about lying to ghosts.  The ability to visit a Ghostly Land and happen across another spirit with a language in common—potentially at any time—rules out nearly all of the most elaborate deceptions one might otherwise attempt.  Of course the risk with lesser fabrications is not so high; one can often lie to ghosts about their geographically-distant relatives quite safely.

Ultimately, interacting with people is a skill you have to develop over time—whether those people be dead or living.  Go with what works best for you on a personal basis, she instructs.

This lady is a fucking sociopath. Wow. Is there more said here on how possession works?

All the ones referenced here have the approximate structure of drawing some diagrams or placing some objects on the floor, and then having the host-to-be stand in a certain spot and perform an incantation.  They're also all time-limited, lasting between hours and a week.  None of them seem to allow the host to take actions while the ghost is in residence, seemingly including by communicating telepathically with the relevant ghost.  But 'Possessing' is its own entire chapter of spells; he sees one on an opposite page where both parties can share at least some control.

So it's not something ghosts ever initiate by themselves?

If he wants to have a guess at that he may need to skip ahead and read the rest of this chapter.

No, no, he's going in order.

The last chapter of the "Background' section is Locations of Note.  Mostly it seems to be a Yellow Pages of ghost tether spots, centered in the Midwest US but with occasional forays into Europe.  Here's a ghost who knows a lot about math; these ones are good at composing music and have done so for spells before; this one rewards in mysterious ways any impressive and interesting magical accomplishments brought before them; this one loves to know what's going on and will do useful tasks for anyone who brings them sufficiently detailed world news.

..."mysterious ways"?

Those are the words it says on the page, yeah.

Incredibly unhelpful, wow. He does make a note of the world news ghost.