Books by politicians are rarely just pages slapped between two covers. They serve as part memoir, part policy, and in no small part advertisement, on the cover a large portrait of the candidate looking patriotic and strong, often into the distance as though looking towards a higher power. With the release of This Is Herman Cain! (exclamation his, and he’s not looking into the sunset, Cain is looking Right. At. You.), Herman Cain, the former CEO of Godfather’s pizza and one of the current frontrunners for the Republican presidential nomination, is the latest in a long list of political candidate to release such wares. Cain’s will debut at #4 on the October 23^rd New York Times bestseller list, behind Killing Lincoln by Bill O’Reilly and Martin Dugard, Boomerang by Michael Lewis, and Seriously…I’m Kidding by Ellen Degeneres. According to Nielsen Bookscan, Cain’s book has sold 17,910 copies in its first two weeks on sale (Bookscan covers roughly 60-70% of the market and does not report ebook sales). It is a fair start for a man who has never been elected to public office and until a few months ago could only be picked out of a lineup by Godfather’s Pizza employees (Cain’s last book, They Think You’re Stupid, sold barely over 4,000 copies in total).

Books by politicians are often hit or miss. Some go on to be massive bestsellers, such as tomes by Presidents Obama and ++George W. Bush and Flags of our Fathers by 2008 nominee John McCain. Some books help a politician shape, preserve, or redefine their legacy. Some go nearly completely unnoticed and unwanted (see O’Donnell, Christine, whose Troublemaker has sold just 2,977 copies, barely enough to cause a an upset stomach let alone actual trouble). In order to put Cain’s book in perspective, its success should compared to his current competition among G.O.P. presidential hopefuls, other conservative and republican figures, as well as his opponents across the aisle.

The following are the most recent and/or the most successful books published by the current crop of Republican candidates for President:

THE REVOLUTION by Ron Paul (Grand Central Publishing, 2008): 147,452 copies in hardcover, 41,555 in paperback

REAL CHANGE by Newt Gingrich (Regnery, 2008): 114,499 copies in hardcover, 18,032 in paperback

NO APOLOGY by Mitt Romney (St. Martin’s Press, 2010): 97,183 in hardcover, 8,547 in paperback

FED UP by Rick Perry (Little, Brown, 2010): 26,417 in hardcover

IT TAKES A FAMILY by Rick Santorum (University of Chicago Press, 2005): 13,472 copies in hardcover

Ron Paul, despite his passionate base, is rarely considered a serious frontrunner for the Republican nomination. Yet Paul’s THE REVOLUTION has posted the best single-book sales of any of the 2012 G.O.P. candidates. Paul’s follow-up books, End the Fed (2009) and Liberty Defined (2011) sold just over 77,000 and 35,000 respectively. Core of Conviction by Michelle Bachmann will be published on November 21^st, and is expected to be a bestseller. Jon Huntsman has not written a book. Gingrich has published 17 works of non-fiction and 8 works of historical fiction. Real Change is his best-selling book of the past decade, and he routinely sells between 50,000 to 80,000 of each of his hardcovers.

While Ron Paul, Newt Gingrich, and Mitt Romney are the top-selling scribes among the GOP candidates, they pale in comparison to former Vice Presidential candidate Sarah Palin, who earlier this month refudiated her most ardent supporters and officially dropped out of a race that she never officially joined. Palin’s 2009 book, Going Rogue, has sold a whopping 1,392,225 copies in hardcover, over 4 times as many as the rest of the current GOP field combined. Her 2010 follow-up, America by Heart, sold a “mere” 285,362, still nearly as many as the entire current Republican field. Palin’s first book is in rarified air, as one of only six tomes by a politician in the last decade to sell over a million copies. The others:

DECISION POINTS by George W. Bush (Crown, 2010): 1,883,101 copies

DREAMS FROM MY FATHER by Barack Obama (Three Rivers Press, 2004 reissue): 1,794,719 copies

MY LIFE by Bill Clinton (Knopf, 2004): 1,278,296 copies

LIVING HISTORY by Hillary Clinton (Simon & Schuster, 2003): 1,153,840 copies

THE AUDACITY OF HOPE by Barack Obama (Crown, 2006): 1,151,357 copies

Obama’s first book, Dreams From My Father, was not a commercial success upon initial publication in 1995 and had even gone out of print before his popular keynote speech at the 2004 Democratic National Convention reignited interest. The Audacity of Hope was published in late 2006 as then-Senator Obama was expected to announce his candidacy, and was an immediate #1 bestseller. Books by Bill and Hillary Clinton, as well as George W. Bush, came out following their exits from the White House. Surprisingly Decision Points by President Bush, who left the Oval office with an approval rating of 22% (the lowest since Richard Nixon), has outsold My Life by Bill Clinton, who exited with 65% approval.

On the other hand, being in the political spotlight does not guarantee supporters will whip out their credit cards. Books by former Speaker of the House Nancy Pelosi and former democratic presidential candidate John Kerry sold poorly despite their political prominence, selling fewer copies than Against All Odds by neophyte Massachusetts Senator Scott Brown.

Despite being the ones who are actually elected to shape and define policy, political candidates rarely reach the astronomical sales levels of the pundits and commentators who cover them. When Bill O’Reilly said in a recent interview with Newsweek that, “I have more power than anybody other than the President,” he was speaking for numerous pundits who wield power in the bookstore to a degree unheard of save those who have held the top office.

Glenn Beck’s COMMON SENSE (Threshold, 2009): 1,138,321 copies in paperback

AMERICA: THE BOOK by Jon Stewart (Warner Books, 2004): 1,665,621 in hardcover

I AM AMERICA by Stephen Colbert (Grand Central Publishing, 2007): 1,008,326

LIBERTY AND TYRANNY by Mark Levin (Threshold, 2009): 964,381 copies in hardcover

LIES AND THE LYING LIARS WHO TELL THEM by Al Franken (Dutton, 2003): 932,704 copies in hardcover, 192,126 in paperback

STUPID WHITE MEN by Michael Moore (HarperCollins, 2002): 719,729 copies in hardcover

A BOLD FRESH PIECE OF HUMANITY by Bill O’Reilly (Gotham, 2008): 709,546 in hardcover

TREASON by Ann Coulter (Crown, 2003): 396,648 in hardcover

LET FREEDOM RING by Sean Hannity (William Morrow, 2002): 378,750 in hardcover

BIAS by Bernard Goldberg (Regnery, 2001): 396,316 in hardcover

Moore, however, has seen his drawing power in bookstores wane. He sold nearly a million copies of Stupid White Men in 2002, 589,190 for Dude, Where’s My Country? in 2003, then dropped to 66,591 for Will They Ever Trust Us Again? in 2004. His latest, Here Comes Trouble, has sold just 19,758 copies in five weeks on sale. Though MSNBC host Rachel Maddow’s first book is finally scheduled for a March 2012 publication (she agreed to a deal back in 2008), other than current Minnesota Senator Al Franken and the Comedy Central duo of Jon Stewart and Stephen Colbert liberal pundits have recently had a hard time at the cash register. Maddow’s former MSNBC colleague, Keith Olbermann, has written three books (not counting an ESPN opus written with Dan Patrick in 1997), none of which have sold more than 33,000 copies, lagging far, far behind many of those who’ve been designated his “Worst Person in the World.”

So far the rising popularity of Herman Cain’s campaign and his constant media presence has led to decent early book sales, though This is Herman Cain! saw a precipitous drop in sales of 59% from its first week on sale to the second. It will take serious staying power in the polls—not to mention the bookstores—to reach the sales levels of his fellow G.O.P. aspirants. But hey, Rudy Giuliani sold nearly a million copies of Leadership, so perhaps book sales aren’t necessarily the “best” indicator of future presidential success.