A young and inexperienced girl suddenly finds herself married to a widower twice her age. Right from the start, the relationship is utterly unequal - by age, by class, and by knowledge. While the girl struggles to find her place as mistress of a great house, she finds enemies in every servant, every neighbour. 
 This is something of a slow burn story, a "psychological horror" that relies far more on building a creepy atmosphere than on any overt sorts of scares. And du Maurier does it so very well. 
 Not only is the narration itself beautiful and poetic, every word has a place, every nuance and connotation and evoked imagery is used to great effect. 
 Du Maurier does an amazing job of controlling the tension in every scene. The most memorable example of this is the preparation for the costume ball, where it's immediately obvious that disaster is coming. It's even fairly obvious what that disaster will be (at least in its generalities). But du Maurier holds back, building and building the tension by describing how very happy the protagonist, and how very much she is not anticipating what we know is about to happen to her. I could hardly breathe through that entire, rather lengthy scene. 
 The characters are all - down to the very last speaking part - alternately monstrous and sympathetic. I hated Maxim, I sympathised with Maxim, I hated Maxim. My heart broke for the protagonist, I found her insufferable, my heart broke for her. The same again with Rebecca, with Mrs Danvers, with Favell... And it was all seamless, without any inconsistency in their characters. 
 This is, quite simply, what a masterfully written novel looks like. It may not appeal to everyone, particularly those who don't enjoy the slow burn type or who have some sort of weird, quasi-inhuman aversion to gothic trappings, but it is a good novel.