by George Orwell
Though I didn't read it until I was around 20, I was first introduced to 1984, and to the dystopian genre, during my teens when the rest of my drama class and I ended up incorporating a lot of dystopian themes into our practical exam. Drama was the one subject in school where the exams were fun, because it was basically a performance!
In the end we did something completely different to the project we started - for various reasons our ideas fell through - but from that moment on I was hooked on this idea of dystopia. I've always loved stories which involve rebellions and people fighting against corrupt governments or monarchies; I grew up with films such as Robin Hood: Prince of Thieves and Braveheart, and with those kinds of stories under my belt from a young age my love for rebels and outlaws was firmly cemented.
Orwell is considered to be the godfather of modern dystopia. If you haven't read 1984 I highly recommend it, though maybe don't read it if you're in a really happy mood. It's bleak and hopeless and numbingly chilling, but it's also just fantastic. Read it!