But between MacArthur’s retreat from Corregidor in March 1942 and his return to the Philippines October 1944, a shadow war played out: An American corporal joined up with American and Filipino guerrillas in the jungles outside Manila. An American businessman living in Manila slipped in and out of the city to coordinate the guerrillas’ work with the eventual return of U.S. forces. And an American woman went deep undercover, passing as a nightclub owner and gathering intelligence from the Japanese officers who were her primary customers.

Their story is the one the veteran journalist Peter Eisner tells in his new book, MacArthur’s Spies: The Soldier, the Singer and the Spymaster Who Defied the Japanese in World War II, which he discussed recently with senior editor T.A. Frail.

First, sketch the security environment in the Philippines—what did the Japanese control, and how tightly?

Japan made quick work of seizing the Philippines. MacArthur fled with his troops to Bataan and Corregidor just before Christmas 1941. Ten days later, Japanese troops marched into Manila unopposed and quickly set up a puppet government and police force. They established firm control in almost every town and city in the Philippines. Newspapers and radio stations began parroting the occupation line. The Japanese said they had liberated the country from American control; they called it “Asia for the Asians,” but the Filipinos never bought that. Travel was restricted, houses and cars were confiscated. Schoolchildren started compulsory courses in Japanese. Food became scarce. And people faced daily indignities. Men and women risked a slap in the face or a beating—or worse—if they failed to bow before every Japanese soldier they encountered. Japan never won the propaganda war.

What challenges did the American corporal, John Boone, face out in the jungle? And what could he achieve from there?

The resistance, which would involve hundreds of Americans and thousands upon thousands of Filipinos, had several phases. At first, it was a matter of survival. Boone and hundreds of others had been separated from their units while fighting in Bataan. They needed food, medicine and shelter; with the help of Filipinos in the hills, they learned to hide and live off the land. Pretty soon, Boone realized Filipinos wanted to join the Americans and fight the Japanese. Early on, they staged harassment raids on Japanese patrols. Boone eventually placed spies inside Japanese military units. They were successful enough that Japanese commanders assigned intelligence units and raiding parties to track them down. While Japan held the cities and towns, the guerrillas operated in the jungles and kept on the move to avoid capture. Some were caught, and a number of rebels died in Japanese raids, but the harassment took its toll. Japan never managed to put down the guerrillas.

How did the American businessman, Chick Parsons, manage not to be imprisoned when the Japanese entered Manila?

In addition to having friends all over the Philippines, Parsons spoke Tagalog and Spanish and blended in. Also, he had papers that allowed him to masquerade as Panama’s consul-general.  He remained in the Philippines until June 1942, when he sailed out with his family—only to return as a spy in 1943.

And Claire Phillips? What in the world was she doing in that war zone?

Claire Phillips was an adventurer and an alluring singer who performed in a bunch of variety shows in the Pacific Northwest. By the time she arrived in Manila, in 1939, she was 31 years old and had been married three times. I like to think she was escaping from something or someone— maybe from the last of those three marriages. No one knows. When the war broke out, she proved to be both an American patriot and a natural con artist. She avoided imprisonment as an American by resurrecting records of her marriage to a Filipino man and passing as a native. Then she opened her nightclub and started gathering intelligence, at times risking her life. Her talent for making up stories was so enduring that when she died, in 1960, she took many of the facts of her life to the grave.

Her nightclub, Club Tsubaki, must have had a lot of competition. How did she keep elite Japanese officers coming through her doors?

She made Club Tsubaki into the happening place in Manila by befriending the top Japanese propagandists, advertising heavily, inviting Japanese celebrities when they were passing through town—and stealing other clubs’ talent. Her right-hand gal, Felicidad Corcuera, was a lovely performer who could sing in Japanese, Tagalog and English. Another of her spy friends, whom they called Fahny, was billed as the Filipina Josephine Baker—a striking coincidence, given that Baker was working for the French underground during the war. It didn’t hurt that Claire used her connections to the underground to secure a steady supply of beer despite rationing.

What roles did these three play in the liberation of the Philippines? To what extent did they enable MacArthur’s return?

Parsons was MacArthur’s point man. He organized submarine supply operations between U.S. military headquarters in Australia and the Philippines, transporting tons of weapons and other supplies and sneaking spies in and out, along with intelligence reports from the guerrillas and the underground. John Boone and Claire Phillips knew they were working for Parsons. Boone was integral in organizing the resistance on Luzon Island, where Manila is located; he said later that Claire’s intelligence was excellent. Perhaps one of her more poignant roles was to support the POWs at Cabanatuan, which housed survivors of the Bataan Death March under horrendous conditions. She sent food, clothing and medicine and wrote letters to the men to build morale. Many of them wrote back to her during and after, crediting her with saving their lives.

Their efforts, of course, must be remembered in context: Hundreds of thousands of Filipinos also fought and died in World War II. “Looking at it in terms of the whole picture of World War II, Manila should be on the map,” Ricardo T. Jose, a prominent historian at the University of the Philippines, told me. “And yet few people know that. It was one of the worst battlefields of the war.”