The Picture of Dorian Gray is one of those classic books everyone should read at least once. I also believe you would be able to re read it multiple times and get more from it each time.
It was written in 1891 by Oscar Wilde, and it is categorized as a philosophical novel although I would add a bit of mystery to that and remove part of the philosophy (as it has to do with some of the dialogues and not the plot itself). It is, of course, mystery as it would be written at the end of the XIX century, so don't expect anything similar to Stephen King or 'Gone Girl'. It was controversial two centuries ago, but no one would really feel that way nowadays.
The main characters are three: Dorian Gray, Lord Henry Wotton, and Basil Hallward, a painter. All three are very different, and their morals and thoughts on how society should act and be perceived are diverse. I would dare to say you will relate to one of them, or understand one of them. What about the other two? You won't like them much. I have read Oscar Wilde based them on three reflections of himself, and it totally makes sense.
It is set in Victorian England, which is a particular setting I like, for both books and movies. Also, if you live in London, you would be able to appreciate the naming of areas, parks, and streets. The story starts when Basil and Lord Henry are talking over the first one painting a portrait of Dorian Gray. How does the story follow? You have to read it for yourself!
I will say, some of the dialogue is skippable if you only care about the plot and the storyline, but it's worth the read if you're interested in the time period, or have a real love for literature.
I knew some of the twists of the story before reading it, and it kind of spoiled it for me a little bit. If you're unaware of any of them, and don't know anything about the story at all, don't research it: just trust me, and read it.
(ps. Any worthy photo I could find to go along with the post spoiled the whole thing).