As long as we're adding books to a dystopian-novel reading list, consider That Hideous Strength - a sort of spiritual prequel to 1984 describing the gradual rise of such a regime. It also might be the last major work in the genre before the atomic bomb, and predates 1984. It's a transitional work, which is both interesting and a source of its limitations -- I'll leave you with Orwell's book review to detail its strengths and weaknesses which should get you an idea: http://www.lewisiana.nl/orwell/

You can also consider Chesterton's The Man who Would Be Thursday, referenced in that review as well.

Yvgeny Zamyatin We 1921. Orwell acknowledged its influence on 1984, and believed that Brave New World was also influenced by it, though Huxley said otherwise. Anthem's resemblance may not be purely coincidental.