Sardonic and funny, this is Bierce's masterpiece along with Occurrence at Owl Creek Bridge.
Essentially, this is a "dictionary" that defines words in the most cynical way possible. While not specifically cruel, many of the definitions are dark or take us to places that are logically true but uncomfortable to sit with--"edible" is defined as being good to eat, like a worm to a toad, a toad to a snake, a snake to a hog, a hog to a man...and a man to a worm.
Bierce was a brilliant writer, and this book is 50% laughing so you don't cry and 50% cringing because he's more accurate than we would like.