What is the author's tone in The Fourth Turning: An American Prophecy by William Strauss?

The tone of the book has a two competing aspects. On the one hand, the book gives off a sense of impeding catastrophe and social struggle. On the other, it emits a serenity and spiritual peace about the ongoing cycle of history. The Fourth Turning is a book of history and prophecy. The authors hold that we are in a period known as the third turning, where social institutions and values are in a state of decay and different parts of society fight against one another rather than cooperate.