Bill Gates is known not only for his voracious appetite for books, but also for his eclectic taste. The billionaire founder and philanthropist has recommended everything from young adult romances, to weepy memoirs, to hefty tomes on the state of the world. Given the breadth of his interests, you'd think that when he heads off for summer vacation, he might opt for a few light page turners.

But apparently not this year.

Gates just released his annual list of summer book recommendations and it is exceedingly light on taut mysteries or frothy romances. Maybe it's the tense state of the world, maybe it's his work on some of humanity's toughest issues, maybe it's just a random mood, but Gates acknowledges that this year his "choices wrestle with big questions. What makes a genius tick? Why do bad things happen to good people? Where does humanity come from, and where are we headed?"

That's pretty far from a description of my usual summer beach reads. But maybe if you want to be as smart and as impactful as Gates, you might want to start by following his lead and swapping light summer reads for some of these weighty suggestions this year.

1. Leonardo da Vinci by Walter Isaacson

Gates calls da Vinci "one of the most fascinating people ever" who "had an absurdly wide range of interests, from human anatomy to the theater." This biography captures the full extent of his talents. "Isaacson does the best job I've seen of pulling together the different strands of Leonardo's life and explaining what made him so exceptional. A worthy follow-up to Isaacson's great biographies of Albert Einstein and Steve Jobs," according to Gates.

Gates it seems has a soft spot for memoirs of dying. First, he raved about When Breath Becomes Air, the autobiography of a Stanford neurosurgeon dying of cancer. Now he's recommending this title. "When Bowler, a professor at Duke Divinity School, is diagnosed with stage IV colon cancer, she sets out to understand why it happened. Is it a test of her character? The result is a heartbreaking, surprisingly funny memoir about faith and coming to grips with your own mortality," he explains.

3. Lincoln in the Bardo by George Saunders

Reviewers loved this strange, dark novel, and so did Gates. "I thought I knew everything I needed to know about Abraham Lincoln, but this novel made me rethink parts of his life," he says. "It blends historical facts from the Civil War with fantastical elements--it's basically a long conversation among 166 ghosts, including Lincoln's deceased son. I got new insight into the way Lincoln must have been crushed by the weight of both grief and responsibility. This is one of those fascinating, ambiguous books you'll want to discuss with a friend when you're done."

If pondering your mortality isn't serious enough for you, then why not ponder, well, everything (really). "David created my favorite course of all time, Big History. It tells the story of the universe from the big bang to today's complex societies, weaving together insights and evidence from various disciplines into a single narrative. If you haven't taken Big History yet, Origin Story is a great introduction," suggests Gates. "The book will leave you with a greater appreciation of humanity's place in the universe."

5. Factfulness by Hans Rosling, with Ola Rosling and Anna Rosling Ronnlund

If you want to improve something, you first need to truly understand it. "Hans, the brilliant global-health lecturer who died last year, gives you a breakthrough way of understanding basic truths about the world--how life is getting better, and where the world still needs to improve," according to Gates, who calls it "one of the best books I've ever read."