Donald Trump becomes the 45th president of the United States today. Yet despite his no-filter rhetorical style, no one is really sure how he will govern—perhaps even Trump himself.

He's a Republican turned Democrat turned Republican again (with stints in the Independence Party and as an independent thrown into the mix) who has been alternatively hawkish and non-interventionist, a free marketeer who adores politicians that help facilitate his construction projects, and a socially tolerant proponent of "New York values" who as a candidate pandered to xenophobes and winked at white nationalists.

He's also the author, or at least the person credited on the cover, of numerous books. In an attempt to glean some indication of Trump's true political identity, I read his three memoirs and three political books. They reveal both remarkably consistent personality traits and an ever-mutating set of political ideals.

In his first book, the best-selling Trump: The Art of the Deal (1987), the man demonstrates traits still recognizable today. His world is already divided between winners and losers, great guys and jerks, classy ladies and phonies. His braggadocio over his many successes is matched only by his paranoia that "bullies" like then-New York City Mayor Ed Koch are out to stop him from receiving his due credit for restoring Central Park's Wollman Rink or to keep him from obtaining the necessary civic support to build "Television City," a commercial and residential real estate project which subsequent books will reveal as Trump's white whale: an obsession always just out of reach.

Then-New York Governor Mario Cuomo (and long-time Koch rival) is hailed as a "winner and a good guy," former President Jimmy Carter is ripped as "unqualified" but credited for having "balls" when he asked for what Trump considered an absurdly large donation to his charity foundation. Much as he fumes over China today, late-1980s Trump feels Japan is "screwing" the U.S. with a "self-serving" trade policy.

By the time Trump: Surviving at the Top (1990) was published, Trump's business model was spread thin, his first marriage imploding in very public fashion, and the sheen of his "go-go eighties" invincibility had completely worn off. But, as Trump writes, "Anyone who thinks he's going to win them all is going to wind up a big loser."

He spends a great deal of the book laying out his battles with the singer-talk show host-media magnate Merv Griffin over a piece of property in Atlantic City that would become the Trump Taj Mahal, the largest casino in the downtrodden New Jersey beach city that went bankrupt only a year after opening and was finally put of its considerable misery last year. Trump also loves to cloak himself in the macho glory of the military and law enforcement, writing that he would "rather address a meeting of fifty FBI agents or Vietnam veterans than do a TV show." All of his books will re-iterate his love of military parades, something he's promised will become a feature of his presidency.

While Trump dotes on his first wife Ivana's business acumen and personal character in The Art of the Deal, and blames himself for their marriage going stale in Surviving at the Top, by the time of Trump: The Art of the Comeback (1997), he characterizes her as a spurned opportunist out to squeeze him for every penny. He even quotes her as saying, with a Czech accent, "I vant my money now."

He also admits to a disquieting tendency to emotionally commit to major life decisions based on his reaction to unrelated tragedies, writing that he decided to separate from Ivana after the death of three close associates in a helicopter crash, and that he proposed marriage to his long-time on-and-off paramour Marla Maples following the mass shooting on the Long Island Railroad in 1993. It should be noted that the lavish Trump/Maples nuptials took place just 13 days after the massacre, casting some reasonable doubt on Trump's claim that grief motivated him to propose.

As ever, "get even," "be paranoid," and "go with your gut" are mantras repeated ad nauseum, and his loathing of "journalism—if you even want to call it that these days" is documented in a nasty letter written to then-New Yorker editor Tina Brown and an extended rant about Wall Street Journal reporter Neil Barsky's coverage of him.

Trump's admiration of "Top Men" like Henry Kissinger—who he claims hung on Trump's every word during their meetings—and the generals he encountered at a private meeting at the Pentagon have him convinced "with these guys and our military capability, anybody wanting to mess around with us would be in serious trouble."

Around the time The America We Deserve (2000) was written, Trump was flirting with a Reform Party bid for president, which might explain why he spends so much time in the book repeatedly bashing paleoconservative commentator and eventual Reform Party presidential candidate Pat Buchanan for what Trump sees as his Nazi apologia, his "intolerance" against "Blacks, Mexicans, and Gays," as well as the many "inflammatory, outrageous" statements that Trump thinks should disqualify Buchanan as a serious candidate for the presidency (Trump also mocks David Duke, the former Klansman who supported Trump in 2016, but who Trump claimed to have never heard of).

Notably, Trump promises as president he would focus on "one term, two-fisted policies, and no excuses."

Interestingly, Trump claims to be "conservative on most issues," but a liberal when it comes to health care. He also says he's for the right to bear arms but supports the ban on assault weapons and longer waiting periods to buy guns. He calls then-Vice President Al Gore "underrated" and excoriates "the moralists in Congress and in the media" for making too much of Bill Clinton's sexual transgressions—some of which he would highlight in great detail during the 2016 campaign. He also has kind words for then-Florida Gov. Jeb Bush (who he would mercilessly rip as "low energy" during the 2016 campaign) for advocating school choice, as well as Bush's father, former President George H.W. Bush, who Trump describes as a good president who should have "spent three more days and properly finished the job" after leading an international coalition to expel Saddam Hussein's Iraqi forces from Kuwait in 1991.

Also regarding foreign policy, Trump warns that "Within five years Iran is expected to have nuclear missiles capable of reaching the continental United States" and thus as president, he would unilaterally bomb their nuclear reactors. He proposes a "Trump National Security Lottery" to fund the nation's "anti-terrorism campaign," and argues against "bogus" arguments that economic liberalization would help Cuba free itself from the shackles of the Castros, claiming "Cuba will be freed by ideas, not by rapacious businessmen lining Castro's pockets and propping up his oppressive regime." He also extends some saber-rattling to the East, writing "Russia has become the world's leading exporter of weapons of mass destruction to America's enemies" and calls for "a preemptive strike on North Korea."

In Time to Get Tough: Make America Great Again! (2015), Trump writes "I'm a lifelong Republican"—a claim he contradicts in his next book Great Again: How to Fix Our Crippled America (2016), where he admits he was a long-time New York Democrat primarily because everyone around him was. He also switches positions on guns, calling the federal ban on assault weapons "dumb," but never disavowing or even mentioning his previous stance.

His tendencies toward strong-man authoritarianism are on full display in Time to Get Tough's chapter "Strengthen American Muscle," which he opens with "Your civil liberties mean nothing if you're dead." Trump offers "Hats off to the Russians" when praising Vladimir Putin's "big plans" to "edge out [Russia's] neighbors so that Russia can dominate oil supplies to all of Europe" and create a "Eurasian nation" of former Soviet republics.

Refreshingly, Trump rips President Barack Obama for launching an "illegal war" with no congressional approval in Libya, but mostly focuses on the cost of the NATO operation rather than the moral or ethical issues of a president unilaterally deciding to commit American forces to a battlefield which poses no direct threat to the United States. Trump offers a variation on the "Take the Oil!" mantra he frequently deployed during the campaign, arguing "Our policy should be: no oil. no military support. No exceptions."

No modern Trump tome would be complete without a bit about Mexico, and in Time to Get Tough, Trump reiterates his "theory that Mexico is sending their absolute worst" to make the U.S. "an annex of Mexico's prison system," which he argues without any data accounts "for the fact that there is so much crime and violence."

What are some of the big takeaways revealed by reading books by Trump and about Trump?

Other than the quintessentially 1980s time capsule The Art of the Deal, all of these books were likely to be forgotten. Indeed, both Surviving at the Top and The Art of the Comeback are out of print and can only be found on the resale market or in libraries. The books show just how long some of his particular quirks have been a part of his personality—for instance, he's been using the phrase "big league" (frequently misheard as "bigly" during the debates) since as early as 1997 in The Art of the Comeback, which is also around the time he began regularly referring to himself in the third person as "Trump."

But now Trump is a part of American history, and though his books read like he talks—frenetic, constantly boastful, and fast and loose with many facts—there are hints to how he will govern.

For instance, Trump is an unrepentant crony capitalist and job protectionist. He likes gaming the system, but is threatened by true competition. He's also a criminal justice refom denialist who believes in harsher sentencing, and on foreign policy, he's alternately non-interventionist one moment and apocalyptically hawkish the next. His authoritarian streak—and admiration for certain dictatorships—was as plain as day from as early as The Art of the Deal.

Trump's model of capitalism has relied on special considerations from city and state governments for nearly all of his major skyscraper and casino projects. That's why he loved Mario Cuomo (for "exerting his influence" during Trump's takeover of the Eastern Shuttle airline) and hated Ed Koch (who he called a "bully," largely for not providing sufficiently favorable tax abatements for Trump properties). He also lays much of the blame for the failure of his Atlantic City casinos on city managers for not coming up with the financing to make the otherwise disastrously depressed city more attractive for tourism.

Relatedly, Trump's nationalism and economic populism aren't late-coming additions to his political persona; they've always been there. China has replaced Japan as economic enemy #1 in his eyes, and he doesn't appear to have supported any of the free trade agreements the U.S. has adopted since the publishing of his first book.

He also has some contradictory ideas about corporations and the legal system. For instance, in Time to Get Tough he argues for tort reform and a $100,000 cap on "so-called pain and suffering" awards in lawsuits, but in The Art of the Comeback, the lifelong teetotaler who lost his older brother to alcoholism writes that lawyers should go after the alcohol industry with lawsuits the way they have with the tobacco industry.

When it comes to criminal justice much of Trump's belief—despite facts to the contrary—that America is enduring a record crime wave appears to stem from his late mother's purse being snatched by a 16-year-old in 1991. Before that, he responded to the infamous rape and beating of a jogger in Central Park by taking out a full-page ad in The New York Times calling for the reinstatement of the death penalty and for politicians to "BRING BACK OUR POLICE…MAKE NEW YORK CITY SAFE AGAIN!" He cites the Old Testament in The Art of the Comeback, writing "I believe in an eye for an eye."

But he possesses inability to admit a mistake or acknowledge facts—such as the fact that violent crime has dropped precipitously since the early 1990s or that the five youths who served prison time for the Central Park jogger rape were in fact, exonerated. He has no time for the "know nothings" of the American Civil Liberties Union (ACLU) and unlike a growing number of Republicans, denies mass incarceration is a problem worth considering. If anything, Trump thinks we have an under-incarceration problem.

Trump's foreign policy worldview is all over the place. In The America We Deserve he promises "No more Clintonesque apologizing" when the U.S. intervenes militarily, but also no more of what he sees as half-measures like the first Gulf War or the bombings of Serbia and Kosovo.

Just when he appears to be fairly non-interventionist, arguing only for the use of military force when the U.S. is threatened, he plainly states he would stage pre-emptive strikes on both North Korea and Iran's nuclear reactors and military installations.

As stated on the campaign trail, he thinks pretty much all of our allies except for Israel (far and away the largest beneficiary of U.S. military aid) have been freeloading when it comes to providing for their own defenses, and Trump would happily do away with using our armed forces to protect places such as Europe, South Korea, and Japan unless they started paying us for such services.

He also has a consistent record of aggressive talk about trade. In Surviving at the Top—more than two and a half decades before he declared "only I can fix it" at last year's Republican National Convention—Trump proposed a blue-ribbon panel of "corporate leaders, independent dealmakers, and other non political figures…to help us forge a new relationship with the world."

His proposed nine-member panel—who he assured "if given free rein…could reverse America's eroding economic status and enhance our country's stature as a role model for the rest of the world in a matter of months"—included General Electric CEO Jack Welch, Ted Turner, Carl Icahn, and former Disney CEO Michael Eisner. Trump writes that the very first thing he'd propose is a 20 percent tariff on imports on "countries that don't play by the rules," such as Japan and Germany. Essentially, if given "free rein," he and other Top Men would immediately start a trade war with any number of countries, for the good of America.

Trump has been accused of having authoritarian tendencies and a temperment unsuitable for commander-in-chief, and his books present a man who has always believed in the "great leader" model, hates decisions made by committee, and considers any pushback against his will to be a personal affront.

He always demonstrates total confidence in himself. The updated Kindle edition of Great Again (formerly titled Crippled America) includes a foreword from Trump where he writes "… [T]he fact that I won the election for the President of the United States is not a great surprise to me. Believe me, I never took this outcome for granted." Throughout all six books, Trump constantly repeats the phrase "believe me." And while there are many unexplained inconsistencies (his paternal grandfather is Swedish in The Art of the Deal, but by the time of The Art of the Comeback, he's German), one thing is for certain, Trump is a creature of emotion.

Far from being a cool, calm, and collected negotiator, he wears his emotions on his sleeve, never admits fault, and believes in sweeping top-down government edicts. In six books, he rarely misses an opportunity to tout his patriotism, but other than the occasional hat tip to the 2nd Amendment, never expresses any affinity for the constitution.

It's Day One of the Trump era, the beginning of presidential memoirs which promise to be unlike any others.