Some people relied on TikTok to get through the past year of Covid. Barack Obama relied on books.

On Wednesday, the former U.S. president posted a list of his favorite books of 2021 on Facebook and Twitter, continuing a 2009 tradition he started while in the White House. "Art always sustains and nourishes the soul," Obama, 60, wrote in his posts. "But for me, music and storytelling felt especially urgent during this pandemic year."

The 13 books on Obama's list this year encompass several genres, but are all penned by American authors and revolve around the human experience. In 2015, Obama told the New York Review that he's long gravitated toward novels that elicit empathy, a trend that continues this year.

Here are his favorite books of 2021:

• "Matrix" by Lauren Groff
• "How the Word Is Passed: A Reckoning with the History of Slavery Across America" by Clint Smith
• "The Final Revival of Opal & Nev" by Dawnie Walton
• "The Lincoln Highway" by Amor Towles
• "Invisible Child: Poverty, Survival & Hope in an American City" by Andrea Elliott
• "Harlem Shuffle" by Colson Whitehead
• "Cloud Cuckoo Land" by Anthony Doerr
• "These Precious Days" by Ann Patchett
• "Crying in H Mart" by Michelle Zauner
• "Aftershocks" by Nadia Owusu
• "Crossroads" by Jonathan Franzen
• "The Love Songs of W.E.B. Du Bois" by Honorée Fanonne Jeffers
• "Beautiful Country" by Qian Julie Wang

Some of the writers are particularly well acclaimed: Colson Whitehead, for example, has won two Pulitzer Prizes and a National Book Award. Others, like musician Michelle Zauner, are relative debutants as authors.

And many are fiction writers. Dawnie Walton's "The Final Revival of Opal & Nev," for example, takes readers through the early 1970s rock scene in New York City through the lens of Opal, an aspiring musician from Detroit.

Decades later, in 2016, Opal's life is distinctly different — part of a story about music, race and family secrets that NPR called both authentic and emotionally powerful.

The non-fiction on Obama's list appears to be just as emotionally gripping. Take Andrea Elliott's "Invisible Child," which tells the story of Dasani Coates, a child living in a Brooklyn, New York, homeless shelter who appeared on the front page of the New York Times for five consecutive days in 2013.

The book follows Coates through the next eight years of her life, showing how growing up homeless contributed to her continued struggles today.

Obama's posts also included a list of books he previously recommended earlier in 2021:

• "At Night All Blood Is Black" by David Diop
• "Land of Big Numbers" by Te-Ping Chen
• "Empire of Pain" by Patrick Radden Keefe
• "Project Hail Mary" by Andy Weir
• "When We Cease to Understand the World" by Benjamín Labatut
• "Under a White Sky: The Nature of the Future" by Elizabeth Kolbert
• "Things We Lost to the Water" by Eric Nguyen
• "Leave the World Behind" by Rumaan Alam
• "Klara and the Sun" by Kazuo Ishiguro
• "The Sweetness of Water" by Nathan Harris
• "Intimacies" by Katie Kitamura

Notably, two of those books — "Project Hail Mary" and "Klara and the Sun" — also appeared on Bill Gates' end-of-year list of book recommendations, which the billionaire Microsoft co-founder published in a blog post last month.

Gates declined to offer much detail on "Project Hail Mary," noting that he didn't want to give away any of the book's myriad plot twists. "Klara and the Sun," he wrote, made him "think about what life with super intelligent robots might look like — and whether we'll treat these kinds of machines as pieces of technology or as something more."

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