Frankenstein by Mary Shelley
Until I read this book, I didn't realize how much is changed for the movies. The monster is not named Frankenstein. He is simply called "The Monster." He's brought to life by chemicals, not electricity. But he did want a mate. I always thought that was just a reason for a sequel.
Victor Frankenstein is a young university student who becomes obsessed with learning the secrets of nature. After two years of study, he discovers "the cause and generation of life." After another two years, he brings his creation to life. But it is hideous and Victor flees from it. When he returns to his room the monster is gone. And on his wanderings, the monster begins to kill people because he is feared and can't make human contact because of his appearance.
The story is told in a series of letters from an explorer, Robert Walton to his sister. He finds Victor and rescues him from the frozen north seas. Victor relates his story to Walton.
The first half of the book was difficult to get through. Victor Frankenstein goes through a lot of "woe is me" until he really begins to tell Walton the story of the monster. Once it gets to that point it gets much easier. You begin to understand the motives for the murders and actually begin to feel sorry for the monster.