For the epigraph to his brisk, entertaining book on professional marathon running, Ed Caesar chooses a passage from Julius Caesar (no relation): “There is a tide in the affairs of men, / Which, taken at the flood, leads on to fortune...” Brutus’s speech sets the mood well enough, though considering what transpired at the recent Berlin Marathon, Caesar might have also looked for a quote from the same play’s punning cobbler, a “mender of bad soles.” About 10 miles into that September Berlin race, the insoles of Eliud Kipchoge’s running flats began to slip out the back and flop around. It looked as if two neon appendages had sprouted out of his calves -- perhaps some revolutionary technology designed by Nike to reduce wind drag? Despite this freak occurrence, Kipchoge won the race in a time of two hours and four minutes flat, just one minute or so slower than the world record (2:02:57) and a mere four minutes from breaking the two-hour mark. Surely the latter is within reach barring a similar wardrobe malfunction? Not exactly. The two-hour marathon, 26.2 miles run at 4:35-per-mile pace, won’t be accomplished anytime soon, which Caesar, a journalist, acknowledges implicitly in the title: Two Hours: The Quest to Run the Impossible Marathon. Elsewhere he calls the land beyond the two-hour barrier “the Narnia of Distance Running.” Seconds don’t come cheap in elite racing, and the two-hour marathon, at least when Caesar was writing his book, was still 218 seconds away: What’s 218 seconds? It’s a pop song; a long commercial break; the time it takes to soft-boil a small egg. In marathon terms, however, those 218 seconds are a lifetime. To produce a solid, let alone world-record, performance, everything has to go exactly right. The best marathoners usually compete only twice a year at a handful of fast, flat marathons (Berlin, London, Dubai). If a runner has an off day, if it’s too hot, cold, windy, rainy, if the pacers, who are world-class runners themselves, don’t hit their assigned splits, or if, say, a shoe disintegrates, then the attempt has to wait another six months. Fear not, though; our best scientists are on the case. The Sub2hrProject in Newcastle, England, has been “launched...to ‘identify and nurture’ a runner who could break two hours within the next five years.” Mike Joyner, a professor of anesthesiology, calculated in a 1991 paper that “given ideal conditions, and the ideal runner,” a 1:57:58 marathon was possible. (And that’s without the benefit of performance-enhancing drugs.) Joyner based his prediction on physiological factors, while David Martin and Holly Ortlund used the historical correlation between the 10,000-meter and marathon world records to predict that the first sub-two-hour marathon would occur between 2029 and 2032. I can’t imagine the pressure that the world’s best marathoner will feel in 2032: If not for personal glory, break two hours to defend the honor of predictive statisticians everywhere! I agree that the time will eventually fall, if only because, as with the 1950s pursuit of the four-minute mile, fate has conspired to align an arbitrary distance with a tempting target: just imagine having a “1” in front of your marathon time. If this logic sounds faulty, so be it, for even in such a hyper-regimented sport, there is an element of the irrational in distance running. As Caesar writes in one of his uncharacteristically overwrought moments: “Human beings are more than hearts and lungs and legs, and the quest for virgin territory more than a battle of swift feet.” Caesar devotes a chapter to the always colorful history of the marathon (always more fun reading about than running). He starts with the hemerodromos (i.e., running messenger) Pheidippides’s fatal journey from Marathon to Athens in 490 B.C., the best “creation myth in sports,” up through 17th-century England, where Samuel Pepys chronicled “endurance races taking place between the servants of the rich” around Hyde Park, an OSHA violation if there ever was one. For the 25-mile race run at the first modern Olympics in 1896, a Greek financial backer offered his daughter’s hand in marriage “for any local man to cross the finish line in first place.” (A Greek, Spyridon Louis, did eventually win, but he opted for “free meals and haircuts for life” instead of the daughter.) The first man to cross the line of the 1904 Olympic marathon in St. Louis hitched a ride from miles 9 to 20; a forbear of Rosie Ruiz, who in 1980 would hop on the T and emerge to “win” the Boston Marathon. The actual winner in St. Louis, Thomas Hicks, downed on course a “cocktail of brandy, egg whites, and strychnine,” an early version of the nauseating energy drinks widely available today. The modern marathon distance -- twenty-six miles, three hundred and eighty-five yards -- was established at the 1908 Olympic Marathon so that the royal family would be optimally positioned to watch the start at Windsor Castle and the finish from their royal box in White City Stadium. They were treated to quite a race between an Italian pastry maker, Dorando Pietri, the American Johnny Hayes, who trained on the cinder track on the roof of Bloomingdale’s, and a South African named Charles Heffernon, who was leading with two miles to go before he cramped up after drinking a glass of champagne. (Brandy and strychnine is one thing, but champagne is just unprofessional.) Pietri took over the lead, then collapsed during the final lap in the stadium and was disqualified for being dragged across the finish line. A tough blow for the Italians, who would have to wait until 2004 in Athens to win an Olympic marathon; there Stefano Baldini prevailed after the leader, Brazil’s Vanderlei de Lima, was tackled by a defrocked priest with four miles to go. Sometimes the sport seems governed by Murphy’s Law. Caesar also gets us up to speed on the current state of the marathon: “Since 2002...not only had two minutes fallen from the world record, but the distance appeared to have changed genre” from a “pure endurance event” to a “speed-endurance event.” Apart from this shift, the model whereby an elite runner spends the first part of his career on the track before moving to the marathon seems to be evolving. Haile Gebrselassie, the great Ethiopian champion, did just that, dominating at the 5,000- and 10,000-meter distances before becoming the first man to break 2:04 in the marathon, at the age of 35. Gebrselassie believes that track work in his 20s laid the foundations for marathon success in his 30s (“If you cut a young tree for timber, you cannot succeed,”) though the 25-year-old Gebrselassie might have had a greater potential for running faster. Major marathons generate and pay out big money, which isn’t to say that the elite marathoners are stars. Caesar describes the average, presumably Western viewer tuning in to watch the start of an elite marathon: What you see is a parade of gaunt, lithe black men with low numbers on their vests, arrayed in the lurid uniforms of shoe companies. Their names are as good as indistinguishable, and their stories mysterious. Caesar attempts to remedy this by profiling Geoffrey Mutai, one of the marathoners leading the charge to lower the marathon record. He couldn’t have chosen a nicer -- and faster -- guy, even if the humble, soft-spoken runner doesn’t quite pop off the page. We first see Mutai trying to get in the zone before the 2012 Berlin Marathon by summoning “the Spirit,” or what the French cyclist Jean Bobet described, in typically sensual Gallic terms, as la volupté: a state of “speed and ease, force and grace.” The Spirit does arrive, and he wins. Mutai is from Equator, a town in Kenya’s Rift Valley perched 9,000 feet above sea level. He is a Kipsigi, “a subtribe of the Kalenjin, part of a Nilotic family of tribes who emerged from the Nile Valley centuries ago, and who now utterly dominate distance running…the most extraordinary sample of geographically concentrated dominance in any sport.” Caesar outlines some of the cultural and genetic explanations for their success: Kalenjin runners have a comparatively active childhood and tend to be “extremely slender below the knee;” their diet is “nearly perfect for an endurance athlete;” they were born at altitude but have sea-level ancestry, an optimal combination for heart and lung efficiency, as David Epstein pointed out in The Sports Gene; and the financial rewards are enormous. Caesar also mentions but pays less heed to evolutionary arguments about Kenyan prowess, from the more plausible -- cattle raiding conferred reproductive benefits on the swiftest over long distances -- to the absurd -- painful Kalenjin circumcision rituals “bred toughness” over the centuries, culminating in an athletic population capable of producing a specimen who can run endless 4:40 miles without flinching. There is much debate about each of these explanations, but Caesar sees Kenyan dominance as a numbers game. A combination of genetic and socioeconomic factors has created the right conditions for world-class marathoners to emerge: “Of the hundreds and thousands of men and women who attempt to have careers as professional runners, these particular athletes play the music of their lives most sweetly.” Mutai was one of 11 children, overcoming an abusive relationship with his father and a bout of teenage drinking to dedicate himself to the sport. He left Equator to train alongside a group of self-coached runners in the remote village of Skyland (Kapng’tuny), this during a time when the region was beset by violence stemming from the disputed 2007 Kenyan presidential election: On long runs, the athletes didn’t know whom they would meet. The marathon runner Wesley Ngetich was killed during the violence by poison arrow. The world marathon champion Luke Kibet was severely injured when he was struck by a stone. Mutai himself narrowly escapes being attacked by a machete-wielding mob just two months before his first international marathon in Monaco. Caesar effectively captures the bemusement that Mutai feels when transported from this alternately ascetic, roiling environment to the Riviera: “Mutai found the place ridiculous. People in Monaco drove their cars in tunnels and treated their dogs in hospitals...Here he was, in this odd place where rich mzungus [whites] lived crushed together, and he had a chance to change his fortunes.” Which he does. Mutai wins the race and goes on to become a world-class marathoner. In 2011, led out by the front-running American Ryan Hall and pushed by fellow Kenyan Moses Mosop and a strong tailwind, he produced the fastest marathon ever run at the time, 2:03:02. (Though the challenging Boston course, for officious reasons not worth getting worked up over here, is not world-record eligible.) Even after raking in prize money from subsequent victories in Berlin and New York, he continues to retreat to a small cottage with no running water and three roommates during peak training periods, heading out up to three times a day -- between naps -- to run on “God’s own racetrack: the dirt roads of Skyland.” This may sound crazy to the millions of Americans forced to listen to their coworkers droning on about their marathon training, but Caesar could have gone into more detail about Mutai’s workouts. Unlike the pair of books by Chris Lear on collegiate runners (Running with the Buffaloes and Sub 4:00), Caesar doesn’t delve too deep into the specifics of the training program, but rather outlines the building blocks -- long runs of around 20 miles that get progressively faster and hills, lots of hills, which “[stay] in the legs longer” than track work. Another staple is the “fartlek,” a Swedish term meaning “speed play” that has been reliably making me giggle for decades. (It involves a continuous run alternating between faster and slower paces.) Really though, the Kenyan training strategy is simple: “We start slow...and then we pick [go fast].” And perhaps we’re overcomplicating what’s needed to run a two-hour marathon, such as devising new shoe technology or constructing a sheltered course with a more forgiving surface than asphalt. Why not cover the first half in one hour or so, and then, in the lapidary parlance of these extraordinary athletes, pick? Easier said than run.