Few people understand fear of the unknown better than Jack Flowers and his fellow tunnel rats of Vietnam.

A combat engineer platoon leader in the 1st Infantry Division, Flowers, equipped just a knife, pistol, hand grenades and a flashlight, would lower himself into one of the dark, narrow crevices 

He and his men had no idea what awaited them. Squeezing themselves through the unlit, narrow passages and slipping through a trap door to another level, danger was everywhere: Enemy combatants, punji sticks, trip wires and booby traps that set off explosives or released poisonous snakes and scorpions, for example.

“It was scary,” Flowers said. “We were pretty well trained, but at the very beginning, if you went into a tunnel, it was almost suicidal.”

The Auburn resident estimates he went on more than 80 such missions. The Chicago Tribune, in a 1985 report, put the number at 97.

On his final mission in 1969, four to six weeks before the end of his tour, Flowers admits he “went berserk.” The stress of the tunnels finally brought him to a breaking point, and Flowers was sent home.

The description of that final descent into a Viet Cong tunnel is the climax of the book “Rat Six,” written by Flowers, that documents his service in Vietnam and the little-known story about the U.S. servicemen who were tunnel rats.

The book is officially a work of fiction since Flowers changed everyone’s names and added romantic embellishments, but the story of lead character Clifford Price consists of Flowers’ Vietnam experience and his thoughts.

The book title refers to Flowers’ nickname “Rat Six.” The six is a designation for a leader or commander. Rat was for his team’s work underground.

Born in Indianapolis in 1944, Flowers attended Rose Polytechnic Institute — now known as Rose-Hulman Institute of Technology — in Terre Haute, Indiana, to study engineering, but left school after two years and was soon drafted. As his collegiate studies made him eligible for officer candidate school, Flowers went to Vietnam in 1968 as a second lieutenant and a combat engineer.

“I had worked with the tunnel  rats,” Flowers said. “When they needed a new tunnel rat leader, they asked me to volunteer. We were all volunteers in that job.  I spent about seven to eight months as the leader of the 1st Infantry Division tunnel rats. It was the longest that anyone had ever served in that position.”

He described the vast tunnel network as a labyrinth, utilizing a series of levels to allow the Viet Cong to travel and hide in the maze of dark passageways. They were also designed to confuse American soldiers who dared to venture underground.

Flowers said some have speculated that of the more than 2,500 Americans still missing in action, hundreds may include “those who went into a tunnel and never came back.”

He credits his tough sergeant, Robert Bateman, who was with the tunnel rats from the beginning and stayed with them for three tours, with helping him survive as a tunnel rat commander.

Flowers received many commendations, including a Bronze Star, but the many harrowing trips into the void, either by him or the men he commanded, began taking a toll.

“They should have replaced me weeks before,” Flowers said. “I tried to quit two or three times because I had too many close calls, but they didn’t have anybody to replace me.”

After his troublesome last trip below, which is detailed in the book, Flowers’ new sergeant convinced the executive officer to send the platoon leader home.

“I still had a month to six weeks left in the country, but they whisked me out,” Flowers said. “I actually got home about 10 days  early.”

He was unaware of how deeply the tunnels were still affecting him until nearly a year later, when he grabbed the throat of his girlfriend one morning when she tried to awaken him.

The incident caused him to examine his life. Suffering from what is now known as post-traumatic stress disorder — “there was no such thing as PTSD then,” he said — Flowers began writing the book as a catharsis for himself. He said it took about four years to complete.

It stayed on a shelf until the mid-1980s, when two British authors who were writing a book about the tunnel rats contacted him. Allowed to read his manuscript, the authors were amazed at the details Flowers had recorded. They devoted one chapter — Rat Six and Batman —  in their book “The Tunnels of Cu Che,” to Flowers and his sergeant, whose nickname was Batman.

As part of the publicity for the book, Flowers was interviewed for “60 Minutes,” “Good Morning America” and “Charlie Rose,” he said.

By then Flowers had graduated from college and was hired by H. Ross Perot  to work on Wall Street.

Now with an agent, Flowers was unsuccessful in getting the book published, but did sign an offer with MGM for a movie, but that deal fell through. Years later, Warner Bros. approached him for the film rights and an option on the unpublished book, but that also failed to go anywhere.

Flowers, who had moved his family to Auburn following 9/11 when his wife witnessed the second plane striking the World Trade Center, was inspired again to try to publish his manuscript following the Ken Burns documentary “The Vietnam War,” which was aired last year.

Page Publishing picked up the rights and officially released the book last week.

The book is available at Amazon, Barnes & Noble and at his website, www.ratsix.com.

In his recently published novel “Rat Six,” Jack Flowers of Auburn tells the story of being a tunnel rat in Vietnam. (Daryn Slover/Sun Journal)