The growing world tennis literature has left a lot professional authors playing the role of unsung hero. An obvious case of this is J.R. Moehringer, an accomplished author in his own right who helped Andre Agassi with Open but then declined to take credit for it on the sleeve.

It also has its share of patsies: Daniel Paisner’s name accompanies Serena Williams on the spine of On the Line, but he apparently lacked the editorial authority to inform Ms. Williams that her book had no coherent point, nor could he convince her that “feel badly” means that your sense of touch is inadequate, as opposed to implying sympathy.

Making out far better than either of those examples is John Carlin, who co-authored Rafa, the “autobiography” of current world No. 2 Rafael Nadal. “Autobiography” has scare quotes attached in this case because while most of Rafa is written in Nadal’s voice, there are sections in between each proper chapter in which he is clearly the subject being described by Carlin.

Or, at least, he is the subject of interviews being conducted by the author.

“… Rafael – a role model for children everywhere – works with more passionate commitment in the gym than any tennis player I have ever come across …” Carlin quotes his trainer Joan Forcades as saying. “… for all the success he has had, he strives with the utmost seriousness in every single practice session to make improvements to his game.”

“Passionate commitment” is the theme of this book, in much the way it was in Pete Sampras’ autobiography A Champion’s Mind. Only in this case, it is detailed more painstakingly: Nadal describes it in the chapters he narrates, and Carlin’s vignettes in between serve as corroborating evidence.

A lot of that is because Nadal is plagued with a chronic foot injury, one so severe it almost drove him from the game into a golf career in late-2005. Well before that injury developed, though, it seems the 10-time slam winner had dedicated himself to suffering for his trade.

This book, more than any other I’ve read by a tennis champion, could serve as a guidebook – or a cautionary tale – for any parent interested in making their child a tennis champion one day. Nadal’s uncle Toni made young Rafa both the worker he is and the humble, self-effacing role model he is through an early regime of work and little praise. He was harder on Nadal than on his other pupils, not only because they were family, but because he insisted that the future champion could “take it.” Furthermore, as Nadal’s junior career grew more and more accomplished, his reward was often to hear Toni downplay those successes, insisting that bigger prizes were always ahead.

The program clearly worked, and it’s now easy to see how Nadal could accomplish his recovery from that foot injury, from his disappointing 2007 Wimbledon loss, and from the catastrophic 2009 season in which he lost his Roland Garros title, failed to even play Wimbledon and spent much of the year held back by injuries and the divorce of his parents.

He did recover in all those cases, and his engrained determination helps explain how he was able to overcome Roger Federer, the greatest player of the Open Era in a 9-7 fifth set.

“Tennis against a rival with whom you’re evenly matched, or whom you have a chance of beating, is all about raising your game when it’s needed,” he says early in the book. “I had my fears — I was in a constant battle to contain my nerves — but I fought them down, and the one thought that occupied my brain was that today I’d rise to the occasion.”

And part of the reason why Nadal has refused to go away despite setbacks is because he is accustomed to playing the role of the underdog. He relates that Toni has consistently reminded him that Federer is more technically gifted than he, despite Nadal’s winning record against The Great Swiss. This is not really in doubt – Federer is probably the best technical player the game has ever seen – but one gets the sense that Toni has never bothered to tell Nadal that he is as natural an athlete as has ever played pro tennis.

To hear this might make Nadal relax, and perhaps deprive him of future success.

A book like this may give pause to tennis-loving parents out there considering such a life for their children. Maybe they have the natural gifts, but can they stand working harder than their peers? Can they endure regularly being told that what they have done is not good enough … yet?

Rafa is organized around the player’s greatest achievements: his first Wimbledon victory in 2008, his epic Australian Open win in ’09, and his completion of the career Grand Slam at the 2010 US Open. This structure allows him to segue to relevant lessons from earlier in life that he would apply later, but does not flow seamlessly: More than half of the book centers around Wimbledon, making sudden shifts in setting to Australia and New York.

That the book isn’t centered around a single match may be intentional, as it’s already been done, most famously by John McPhee’s Levels of the Game, but also by Jon Wertheim’s Strokes of Genius (also about the 2008 Wimbledon finale) and Marshall Jon Fisher’s A Terrible Splendor.

Autobiographies of athletes, however, shouldn’t be judged entirely by their literary merits, but whether they teach us something new about the players. Open was well-written, but wouldn’t have mattered if it hadn’t showed us how far Agassi fell before he eventually triumphed. On the Line’s writing was unimpressive, but its great sin was that its story ultimately amounted to nothing.

A bigger potential flaw than Rafa’s structure is that the story hasn’t yet arrived at a proper end. Yes, he has already had enough of a career for a dozen players, but Nadal’s story is still being written. Novak Djokovic – another player Toni considers technically superior to his nephew – has now surpassed both Nadal and Federer in the rankings. Plus, the 2011 season made it clear that his game challenges Nadal even more than Federer’s did.

If the Spaniard fails to rise to that challenge, it won’t negate his achievements but it certainly will cast them in a different light later on. If he does, it will be as though Rafa’s unwritten coda was as consequential as its climax.

What Nadal and his partner Carlin offer here is good. What’s coming, though, may be just as important.