The Colour Purple is a heavy book by Alice Walker that I nonetheless urge everyone to read at some point in their life.

Our protagonist, Celie, is a black woman living some time in the Southern US (since I'm not as well-versed in US-centric history, it's very likely that I missed some historical landmark that could have pinpointed the exact date and timeframe during which the novel is set. Celie's life is a struggle she accepts quietly and mutely - because she sees no point in rising up. After getting pregnant two times by her own father, she gets out of her family by (basically, since there is never a true ceremony) getting married to another man. We never learn his family name, since Celie only ever calls him Mr.---, and his surname is also mentioned only a couple of times, hammering home the distance she feels to the man who is supposed to care for her like the loving husband he is supposed to be (which he is not). Slowly, however, Celie gets to know other people, and herself in the process, among them the notorious singer Shug Avery - a woman she inevitably falls in love with.

The entire novel is basically told via letters or prayers to God, and later as a letter exchange between Celie and her sister Nettie. There is no direct speech per se, and if there is, it is not marked by quotation marks, a fact that might trip you off at first. 
Despite all the darkness and admittedly horrible scenes in this book (Celie's abuse at the hands of her father, her husband, basically every man she ever meets in her life, her pregnancies at 14, her two children being given away pretty soon after birth), I found this novel to be almost equally hopeful at times. The love between Celie and Shug, despite not always being perfect, gave them both the strength they needed to go on. Celie finding purpose in life, even getting to know her husband the way she should have had been able to spend time with him all along, was a beautiful story to witness. She didn't have to change her world to fit her, she just had to find a way to take space where she had always been, and I think that is wonderful.

Overall, this is a heavy book but an impactful one that I think everyone should have read at least once in their lives!