Geralt of Rivia is a witcher, not by choice but by destiny.
The first book Last Wish tell a series of short stories of his adventures, from breaking curse, being cheated, facing angry elves and nasty humans.
In this book, he retold the story of how he met Yennefer and how he is currently avoiding her.
In this story world, some of magical creatures are real while the other is completely fictional. The important of doing what's right and keeping a promise is important to Witcher. Also, in the story world, Witcher is not welcome as he uses magic. The attitude of humans towards magic is not that good.
Temples and gods exist also in this world. Or at least the priestess. The fights are violent and brutal. No wonder it is so well adopted into video game.
Didn't know about it until Netflix adopted this into a TV series. It is pretty awesome.
Highly recommended for Witcher fans.