This is exactly what the title proclaims it to be: a very short introduction to horror.  It touches on a variety of different flavours of horror: Monsters, occult, body horror, psychological horror, and scientific horror, and gives a brief overview of them from a critical analysis perspective. 

It is just a brief introduction, so none of the analysis goes super deep. But newbies to analyzing horror through a critical lense will find if useful, and even oldbies might find something useful in the pages. If not, it is, at least, extremely readable; it is not bogged down with academic writing, and even if you haven't read or watched everything it discusses, you can still understand the central arguments (but it's even better if you have).