History, in the eyes of legendary investor Ray Dalio, is a perpetual motion machine. Nations rise and fall according to an inevitable cycle where peace and prosperity are always followed by depression and war. And in his new book, “Principles for Dealing with the Changing World Order,” Ray says the United States is now in the downward part of that cycle.

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“The average human lifespan is absurdly, terrifyingly, insultingly short.” So begins Oliver Burkeman’s new book, “Four Thousand Weeks: Time Management for Mortals.” Make it to 80, and you’ll get about 4,000 weeks. And so, as the poet asked, “What will you do with your one wild and precious life?” For most of us, the answer is obvious: Get busy. Why squander what little time we have? But in this conversation with Next Big Idea Club curator Malcolm Gladwell, Oliver proposes an alternative. If you want to make the most of your time, he says, you have to stop chasing pointless productivity and embrace life’s finitude.

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When it comes to Elon Musk, it can be hard to separate the man from the myth. But in her new podcast, “The Evening Rocket,” Harvard historian and New Yorker writer Jill Lepore manages to see through Musk’s mystique, explain his worldview, and decipher his visions of the future by going back to the sci-fi stories he grew up on — stories, Lepore says, that Musk sometimes misread.

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