First off, this book is intense, very well known, and a LOT has been written about it. I read some analysis after I finished just to see what else has been said, but I don't think it altered my initial reactions that much. 

Something I definitely didn't know before I sat down to read this is that the novel is actually a collection of three separate but connected novelettes (published over the course of several years), each told from a different POV: Yeong-hye's husband, her sister's husband, and then finally her sister. 

Yeong-hye (The Vegetarian referred to in the title) doesn't get her own section, and it becomes clear as you progress through the book why that is. While she does decide to become a vegetarian (vegan actually) after a dream, this decision is the starting point of a serious deterioration of her mental and then physical health. 

The three novelettes in this collection cannot be told from her POV, because she's in no state to provide one. Rather, the book is actually about how Yeong-hye's conditions affect those around her. The husband and brother-in-law are absolutely despicable and selfish monsters, and the sister is left to pick up the wreckage of her sister's decline completely alone. 

The book, despite the misconceptions I think surrounds it, is bleak, but beautifully written. It's definitely a hard book to read, but it's one that I suspect will stick with readers long after they finish it.