What does the title Brave New World mean?

The title Brave New World is a reference to Shakespeare's The Tempest. The line is delivered by Miranda, a young girl who has grown up on an isolated desert island, having known only her father and his deformed slave, Caliban. When Miranda meets men from the outside world, she says: "Oh brave new world, that has such people in it!"

This situation somewhat parallels that of "John the Savage," who has grown up on a reservation isolated from the modern world of technology and pleasure. Unlike Miranda, however, whose exposure to the outside world is full of promise and potential, John ultimately finds himself disgusted by the future society in which he finds himself, and is totally unable to adapt to it.