When Barack and Michelle Obama signed their joint $60 million book deal in 2017, two months after moving out of the White House, industry insiders were initially stunned and skeptical. Not only was it the highest advance in the history of book publishing, it was also more than twice what the Obamas had been expected to get. Publishers Weekly called the deal a "mystery" and a "gamble"; Vox doubtfully calculated that the couple would need to "sell at least several million copies all together" for it to be worth it. Others pointed out that Bill Clinton comparatively earned just $15 million for his 2004 presidential memoir, which had been record-breaking at its time.

But nearly four years — and one Becoming by Michelle Obama — later, there is no more "mystery." Rather, Barack Obama's post-presidential legacy looks very much like it might be his literary star power.

On Monday night, fans in Washington, D.C., braved a pandemic to queue for the midnight release of the first part of Obama's two-volume memoir, A Promised Land, despite such an activity being more typical of a new Harry Potter installment. Other bookstores around the country urged customers to preorder, or come in early to pick up their copies, as restocking delays are expected. Penguin Random House had initially ordered a first printing of 3 million copies of Obama's book, then bumped it up to 3.4 million based on overwhelming early interest. It reportedly took 112 shipping containers to get additional copies back to the United States from Germany, where printers were handling the extraordinary demand (that's not to even mention the book's international editions, which are being translated into 25 languages including Chinese, Finnish, and Vietnamese).

Somewhere along the way, A Promised Land began to take on expectations much bigger than the juicy gossip that typically lures readers to political memoirs, too. The book is now being hailed as a potential life preserver for brick-and-mortar bookstores that are struggling during the pandemic. "This will be a book of rare consequence," Barnes & Noble CEO James Daunt told Publishers Weekly. "That it will sell as no other book has done since July 21, 2007 [the publication date of Harry Potter and the Deathly Hallows] is immensely cheering to booksellers."

Still, there had been a brief moment there where it seemed like Obama might sail off into post-presidential obscurity on a French Polynesia-bound megayacht laden with celebrities. How did he become poised to be the biggest author since J.K. Rowling (or, well, at least since E.L. James)?

Obama, admittedly, has always been a bookish sort, whether in his own poetic oration or in his annual year-end reading lists, which demonstrate his broad literary tastes. "Whether as candidate or president, Obama knew it came down to words, the way they spun and gathered, lifted and fell on precise beats with restrained flourish," the Los Angeles Times wrote in reflection at the end of his presidency. "He was a writer before he was a president," David Litt, one of Obama's former speechwriters, added to The Wall Street Journal. "He understands the value of story." Obama certainly has a writer's eccentricities, anyway: he wrote the first draft of A Promised Land longhand, but ended up with so much material that he decided to break the project up into two volumes. (Writer types also circulated, with hints of envy, a screenshot of Obama's interview with The Atlantic, in which he admitted to shaking off his editor's suggestions to be more succinct). The result, though, is that unlike many dreadfully boring presidential memoirs of yore, "Obama's track record as a writer … suggests that his book could get a boost from actually being good," The New Republic writes.

Don't discount the Michelle Obama effect, either. The former first lady's memoir, Becoming, was the first part of the $60 million book deal to be delivered to readers, and a runaway success, selling 8.1 million copies in North America since it came out in late 2018. (By comparison, E.L. James' Fifty Shades of Grey, the top-selling book of the last decade, sold 15.2 million copies in the U.S. ... over eight years). There is still some doubt A Promised Land will actually beat Becoming, with Axios claiming "the ferociously competitive Obama knows he's unlikely to outsell" his wife. (A Promised Land's $45 price tag probably doesn't help either). On the other hand, the buzz built by the success of Becoming combined with sustained interest in Barack Obama could make A Promised Land a publishing supernova. The book "should be expected to sell in the millions, if not tens of millions," The New Republic's Alex Shepherd predicts, adding that it could very well be "the biggest book of the year and possibly the decade to come." Barnes & Noble, meanwhile, is stocking around half a million copies with the expectation of selling even more, based partially just on how well Becoming was received.

And that's just considering the initial response to the book in the immediate weeks and months. But presidents don't write books to be the next J.K. Rowling — they write for their legacies. As Vox noted in that dubious initial assessment of the book deal, "a really good Obama book has the potential to become a genuine classic," something that earns a place beside Personal Memoirs of Ulysses S. Grant and The Life and Selected Writings of Thomas Jefferson. Maybe it will turn out that A Promised Land's worth isn't in breaking bestseller records, but rooted in a more historic importance, as a tome to be referenced and reflected upon for decades or centuries — or at the very least, to sit prominently on bookshelves in the background of Zoom meetings, signaling an owner's level of education and engagement.

By all indications so far, though, it will be both. Obama's book hasn't been out for 24 hours, yet already it is a sort of political Harry Potter, on the cusp of once-a-decade sales.

And then there'll always be volume two.