The book itself is short and to the point, building itself just like a suspense or horror tale from late night radio. This story could easily be a radio script. With the tale's simple language and minimal description, the story weathers its age far better than expected despite its period 70's foundation. The first quarter develops the setting, the second quarter develops the fear, the third the anxiety, and the fourth the panic.
For its slim size, this little volume sure packs a wollop, much like a bigger or longer book. If it had been written in a more literary style, it would have proven just as large. As its writing is so tight, you can't skim through the book.
The horror of this story isn't in what happens, but in the whole premeditated scale of it all. As in all the best horror stories, humans make the scariest monsters of all.