Want to run for president? You better write a book first, as every 2016 hopeful quite obviously knows.

Books can be a useful tool for presidential contenders, even in the digital age.  And they can be a lucrative endeavor, though some more than others; Rep. Paul Ryan didn't get a dime for his upcoming book, while Texas Sen. Ted Cruz just signed a book deal with HarperCollins for an estimated $1.5 million. 

It's Cruz's first book, so we won't know just how presidential his manifesto will be, but that doesn't mean we can't judge his competition. We decided to do so not by reading the books, but through the classic American tradition of reading blurbs on Amazon and looking at the book covers. We put on our "general election voter" caps and gave out scores based on what we saw. Here's how each candidate fared.

1. Marco Rubio

Sentinel 

Title: An American Son: A Memoir (10/10)

Advance: $800,000

Amazon blurb: "Devastated after his grandfather’s death, Rubio was getting poor grades and struggled to fit in at his high school, where some classmates mocked him as 'too American.'" (9/10)

Does it work? While this might seem like a knock-off of a certain audacious former senator, Rubio gets straight to the point: he's American (you might say "too American"), and he's somebody's son. America. Family. That's a winning combination.

Rubio is going for as broad appeal as possible. If you love America, and you love sons, how can you not love him? The title suggests he was literally birthed by America. This is a personal chronicle and manifesto, which means it's all about him, like any good campaign should be. And just look at him: legs spread wide, hand on knee, no tie. Rubio is casual, but rock solid. Like the perfect American son. (Overall score: 19/20)

2. Rick Perry

Little, Brown and Co.

Title: Fed Up!: Our Fight to Save America from Washington (7/10)

Advance: N/A (Perry didn't take an advance for his previous book, and when he signed this deal, it was reported any proceeds would be donated to charity.)

Amazon blurb: "Now, do not misunderstand me, America is great." (10/10)

Does it work? Whatever's written inside the book must be exceptionally terrible, because this cover should've won him the Republican nomination in 2012. Red, white, and blue cover? Check. Exclamation point? Check. Forward by Newt Gingrich? CHECK. And that blurb? Make no mistake: Rick Perry is in love with America. He wants to be very clear about that. He's so in love with his country, in fact, that he wants to shout it from the mountaintops, as he appears to be doing on the book's cover. This is truly inspiring stuff. It's not as tug-at-the-heartstrings effective as Rubio's, but that's not really Perry's style anyway. (Overall score: 17/20)

3. Rand Paul

Center Street 

Title: Government Bullies: How Everyday Americans Are Being Harassed, Abused, and Imprisoned by the Feds (Score: 8/10)

Advance: $300,000-$400,000

Amazon blurb: "Unelected bureaucrats, armed with arbitrary rules and no need to back them up, stonewall and attack American citizens at every turn." (7/10)

Does it work? Arms crossed, stern-faced in front of the Capitol building, Paul is serious: no more government-sanctioned bullying. Like Santorum, he's going after "Everyday Americans" with this one, but his is slightly more inclusionary, and hits on more of the things that Joe Plumber hates. Unelected bureaucrats! The Feds! Paul's book has a clear message: everyone in D.C. not named Rand Paul is a villain. Also, is the bully theme a preemptive dig on Chris Christie? If so, bravo. (Overall score: 15/20)

4. Joe Biden

Random House

Title: Promises to Keep: On Life and Politics (4/10)

Advance: N/A

Amazon blurb: "It is also an intimate series of reflections from a public servant who refuses to be cynical about political leadership." (5/10)

Does it work? This has a lot of the same problems as Jindal's (below), as it feels like your run-of-the-mill political memoir. But Joe Biden is front and center, which is important in having an impact on voters. You want to remind them who they're voting for, and with old Joe smiling down from the bookshelves, it'll be hard to forget. Hopefully his "intimate reflections" are riveting. Knowing Biden, they probably are. (Overall score: 9/20)

5. Rick Santorum

Regnery Publishing

Title: Blue Collar Conservatives: Recommitting to an America That Works (Score: 4/10)

Advance: N/A

Amazon blurb: "Enough with pandering, enough with focusing on business owners to the exclusion of everyone else – the vast majority of Americans – who work for them." (Score: 4/10)

Does it work? Santorum's latest feels a little exclusionary. Blue collar workers? What about America's long-persecuted rich? We get the point of this, but spurning business owners might come back to bite him. Santorum is clearly going for a specific targeted voter approach with this one, but that's no way to win a general election.

Plus this cover is all wrong. He's got the eyes and the smile, sure, but what about the rest of him? We can't even see the strong hands from which he can pull himself up by the bootstraps, like a real blue collar conservative. (Overall score: 8/20)

6. Bobby Jindal

Regnery Publishing

Title: Leadership and Crisis (2/10)

Advance: $50,000-$100,000

Amazon blurb: "Throughout his meteoric career, Jindal has dealt with some of the worst crises of our times, from natural disasters in his home state to out-of-control spending in Washington, D.C." (3/10)

Does it work? It's a nice try, but, man, this is boring. First, the title could be about anyone, and in fact it sounds like the title of an 11th grade history essay about Abraham Lincoln. Second, Jindal is either the shortest or second-shortest person in the picture, which doesn't exactly scream "leader of the free world." It's sort of the same blanket voter approach as Rubio's, but far less effective. The cover feels like a cookie-cutter approach to candidate books. (Overall score: 5/20)

7. Paul Ryan

Title: Where Do We Go from Here? (1/10)

Advance: $0, because of House rules. But don't feel too bad: he still gets to reap royalties.

Blurb: "It will challenge conventional thinking, renew the conservative vision for 2014 and beyond, and show how it is essential for the well-being of our communities and the future of our nation." (3/10)

Does it work? Rhetorical questions are pedantic, Paul. There's no cover yet, but it has a lot of work to do if Ryan's to overcome that title, which sounds more like a series of travel guides than a candidate's pre-campaign offering. And from the blurb it sounds as if this will have little to do with Ryan the person, which is a big mistake. We know you're wonky, Paul, but voters want a candidate they can relate to. Whatever happens, though, it can't be much worse than Ryan's last book, which he shared with House Majority Leader Eric Cantor and House Majority Whip Kevin McCarthy. Nothing says "presidential candidate" like sharing a cover with your bosses. (Overall score: 4/20)

8. Andrew Cuomo

HarperCollins

Title: All Things Possible: Setbacks and Success in Politics and Life (2/10)

Advance: Not disclosed, but he definitely got one.

Blurb: It "will discuss not just politics but family and duty, setbacks and successes, as Cuomo considers what his zigzag trajectory has taught him." (1/10)

Does it work? Let's talk about the creepiness of this cover. Cuomo is standing with hands folded in a nondescript room, staring at us with dead eyes and looking more like a wax statue than an actual human. That, right there, has this book DOA. And the content of the book does it no favors? All Things Possible? Let's not get carried away.

And you know what's the cousin of "zigzag"? Flip-flop. For a guy who's been campaigning for president pretty much since his inauguration as governor, we expected better of his campaign book. (Overall score: 3/10)

Doesn't Even Have To Try: Hillary Clinton

Title: TBA, but Clinton suggests Bossy Pantsuit (If actual title: 1 zillion/10)

Advance: She received $8 million for her last one.

Blurb: According to Clinton: "It’s about my experiences in the State Department ... Our rapidly changing and increasingly interdependent world, and the challenges facing us in the 21st century from Crimea to climate change." (4/10)

Does it work? The great thing about this book is that it doesn't have to do much.  It could just be Texts From Hillary in book form and it would still sell like crazy. 

Really, this is just a reminder that "Hey, I'm running in 2016 and y'all loved me when I was Sec. of State." A candidate book battle is the sort of fight she doesn't even have to show up for, so we'll give Hillary the benefit of the doubt. (Overall score: She is going to win the Democratic nomination.)