Combat Outpost Marjah, Helmand Province, Afghanistan, Oct. 16, 2012—It’s been nearly 48 hours since we have been able to send or receive e-mail. Now that we’re back inside a U.S. base with access to the Internet, my inbox is full of mail—all requiring immediate response. The question above—“Why Do I Write?” relayed by my publisher, Simon and Schuster—is at the top of the stack.

After several weeks in the field, I’m dirty, tired, in great need of sleep, a shower and a shave. So are all the young Americans around me. I will be home in a few weeks. They will still be here. They are the reason I write.

All my books, fiction and nonfiction, are about heroes—people who knowingly put themselves at risk for the benefit of others. It’s a privilege to keep company with heroes. They inspire me. The soldiers, sailors, airmen, Marines and U.S. civilians here at this outpost, and the special operators I was with in the shadows of the Hindu Kush last week, are the embodiment of courage, competence, commitment, integrity, and tenacity in the face of great adversity. Their families at home make extraordinary, unsung sacrifices while hoping and praying for the safe return of loved ones serving in harm’s way.

Heroes Proved, the sequel to Mission Compromised, The Jericho Sanction, and The Assassins, is a novel. It’s also about real heroes—the kind of people with whom I have spent my entire life. Experience in war, service as counterterrorism coordinator on the National Security Council staff in the Reagan administration, and more than 50 overseas embeds covering U.S. troops in combat for Fox News provide context and material for these books. But telling these stories presents the prospect of disclosing information or identities that would put brave men and women in even greater peril. That’s why these are novels—where actual names, dates, places, and classified tactics, techniques, and capabilities are altered.

The dialogue and action sequences in these books are akin to what actually occurred during events to which I have been an eyewitness—and sometimes an unexpected participant. Having “been there, done that” is a significant advantage when crafting a realistic, suspense-filled story replete with adrenalin-pumping threats, high-risk challenges, unforeseen dangers, and unpredictable outcomes. If all this causes readers immersed in the story to lose some sleep, good—because that’s what really happens to heroes proved in difficult and dangerous places like this. Semper Fidelis.

Oliver North is a combat-decorated Marine and recipient of the Silver Star, Bronze Star of valor, and two Purple Hearts. From 1983 to 1986, he served as the U.S. government’s counterterrorism coordinator on the National Security Council staff. His 11 previous fiction and nonfiction titles have all been New York Times bestsellers.