Running is the simplest of sports. It deserves a simple book. That’s why I wrote Run Forever.

In the last twenty-five years, running has grown massively popular and increasingly complex. There are too many shoes, drinks, energy bars, training plans, stretching devices, massage tools, and books willing to dissect and discuss all of them.

I’m here to say the opposite: running is not complicated. Run Forever doesn’t attempt to explain everything there is to know about running. It explains only what you need to know. It drills down to the essentials.

I’ve organized Run Forever in a clear and easy-to-follow manner. There are just six main sections: “Getting Started,” “Nutrition for Runners,” “Going Farther,” “Dealing with Injuries,” “Getting Faster,” and “Running Forever.” Even though it contains a training plan for half marathons and marathons, which some might consider the ultimate running challenges, “Going Farther” precedes “Getting Faster.” Both require consistency and determination. But “Getting Faster” is the harder of the two, because it also demands specialized workouts and true grit.

Each section contains ten to twelve “chaplets,” as I call them. These provide short, concise summaries of key information, and conclude with at least three direct actions to follow.

Everything you’ll read on these pages has emerged from my half century of running experience, the testimony of the world’s best runners and coaches, and the scientific conclusions of top running researchers.

At the personal level, I’ve road tested every piece of advice in Run Forever. Over the last fifty-five years, I’ve run 110,000 miles—more than enough to make lots of mistakes (bad for me) and figure out better ways (good for you).

Once I was fast. I was fortunate enough to win the Boston Marathon in 1968, and to run a 2:14 that year. Now I’m slow. I’m a happy member of the “back of the pack” gang. And I’m proud to be there.

I’ve finished the same Thanksgiving Day 5-miler fifty-five years in a row. A few days after this book is due to be published, I hope to complete the Boston Marathon on the fiftieth anniversary of my win in 1968. Along the way I’ve run marathons with Will Ferrell and Oprah Winfrey. If they can do it—and both did, finishing their races impressively—so can you.

Many friends helped me write this book. In four decades of work at Runner’s World magazine, I had long discussions with hundreds of elite runners: Frank Shorter, Bill Rodgers, Kathrine Switzer, Grete Waitz, Joan Benoit Samuelson, Deena Kastor, Meb Keflezighi, Ryan Hall, Shalane Flanagan, and more. Their wisdom and insight is woven throughout Run Forever.

I also have a consuming interest in sports science, and have interviewed many of the leading lights of the last half century—Ken Cooper, David Costill, Ralph Paffenbarger, James Fries, Jack Daniels, Tim Noakes, Steven Blair, and more. Their evidence-based findings underlie the most important concepts in Run Forever.

My high school coach and mentor John J. Kelley, winner of the 1957 Boston Marathon, played a bigger role than all others combined. Not because he compiled a lengthy list of running rules, but because he lived true. He taught me that one’s actions, philosophy, and guiding principles—the simple, big-picture stuff—are far more important than the day-to-day minutiae. I try to remember this lesson every day, and to live by it.

Certain themes return frequently in Run Forever. That’s because they are so central to healthy running. One of these is a practice I call “adaptive excellence.”

I believe we should always aim high, but appropriately. Today it takes me two hours longer to finish the Boston Marathon than it once did. But I’m still moving along. To every thing there is a season—a time to run fast, and a time to run slow and relaxed. But we must continue to pursue excellence, even as we adapt to new circumstances.

Other themes: Listen to your body. Less is sometimes more. Hills are good for you. Recovery is a necessary part of peak performance. Run-walk builds fitness many different ways. Patience and consistency are eternal virtues.

In my twenty years as executive editor of Runner’s World magazine, we regularly asked readers how long they planned to continue running. The response was nearly always the same: 99 percent said they wanted to run for the rest of their lives.

That’s my goal too. And I bet it’s also yours. Ultimately, it’s the main subject of Run Forever.

Running doesn’t get easier with age, but the payoffs grow greater. While none of us can know for sure that running will add years to our life, there’s no doubt it will add life to our years. Which is far more rewarding.

The most important aspect of Run Forever is its emphasis on the mind. The book begins with a “Brain Training” chaplet and ends with one. That’s because I believe running is not so much a physical challenge as a cognitive one. Running doesn’t depend on the size of your heart, the length of your legs, or the cholesterol content of your blood. They are entirely secondary. Your brain rules all.

You don’t need to do twenty-five squats today to build your quad muscles. You need to think five positive thoughts about your motivations for running, fitness, and lifelong health. Because it’s not the quads that will get your legs moving, it’s the thoughts.

Life is not a part-time sport. It’s a full-time challenge. President Teddy Roosevelt said, “The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly.” Few would disagree with this view.

No one wins every race, but we are the better for engaging. If we sit on the sidelines, we can only wither away.

I believe that every run is a new adventure, and every mile a gift. I hope Run Forever will make you feel the same.

Stay the course. Run long and healthy.