As discussed, utopian and dystopian visions constitute a large movement in political and fictional writings. More's Utopia is always a good place to start, as well as any others mentioned in the above text. Other ones to consider are Arthur Koestler's Darkness at Noon (1940) and We by Yevgeny Zamyatin (1921). Incidentally, the widely suggested influence of We on Brave New World was denied by Huxley.
The scientific facts and theories behind the concepts that Huxley touches on are wide-ranging, and many are still beset with controversy. However, the potential polymaths among you should take a look at The Origins of Virtue by Matt Ridley (1996), a revealing and accessible insight into human behaviour, the "nature versus nurture" debate, and the science behind political visions and social reality.
Brave New World Revisited (1958) is Huxley's own attempt to re-evaluate his work, and survey contemporary society in the light of his earlier predictions. Huxley's other utopian novel, Island (1962), written towards the end of his life, is worth examining for its correspondence and contrast with Brave New World.