The book also has a lot of stuff on different kinds of monsters. With a focus on what their scary powers are and how to kill them.
Zombies and skeletons are not people but liches can be, vampires are people, oozes and slimes aren't, trickster spirits are, werewolves are people who only sometimes can control themselves transformed, shades are ghost-things that like to make people pissed off and impulsive and are sorta debatably people, poltergeists are people but not former living people they're just blobs of mischief, there's a few different kinds of tentacle-blob monster and some of them are people. Abyssal Demons are a big category with the following tells (not perfectly reliable): Black, purple, and red, leave things rotten or rusty after they pass, slimy and 'feels unwholesome', distorted-sounding voices like a chorus of off tune singers, often weak to silver (but not always). There's a pretty staggering variety of Abyssals. Spitters, pit traps, spike boars, one-eyed crows, phase wolves, spikewheels, brutes, exploders, headcrabs, giant mosquitos, fire beetles, screamers, hellephants, Death Machines (possessed animate scrap metal), and more.