This hugely influential work marked a turning point in US history and culture, arguing that the nation's expansion into the Great West was directly linked to its unique spirit- a rugged individualism forged at the juncture between civilization and wilderness, which - for better or worse - lies at the heart of American identity today. Throughout history, some books have changed the world. They have transformed the way we see ourselves - and each other. They have inspired debate, dissent, war and revolution. They have enlightened, outraged, provoked and comforted. They have enriched lives - and destroyed them. Now Penguin brings you the works of the great thinkers, pioneers, radicals and visionaries whose ideas shook civilization and helped make us who we are.