I am not a fan of pseudo-scientific magic mumbo-jumbo. I don't believe in time travel, no matter how any author likes to explain it and weave it into their stories.
However, I did like the part where Dana, the main character, goes back in time to the time before the Civil War. I like the description of that time. If Octavia E. Butler had kept to that time alone, this would have been a brilliant book. She knows how to write, she knows how to create a story, she should have stuck to that.
From the back cover: "Dana, a modern black woman, is celebrating her twenty-sixth birthday with her new husband when she is snatched abruptly from her home in California and transported to the antebellum South. Rufus, the white son of a plantation owner, is drowning, and Dana has been summoned to save him. Dana is drawn back repeatedly through time to the slave quarters, and each time the stay grows longer, more arduous, and more dangerous until it is uncertain whether or not Dana's life will end, long before it has a chance to begin."