Take a Boston police detective distantly related to General Eisenhower’s wife Mamie, make him into a United States Army officer, add a backdrop of World War II and an unsolved murder or two, and what do you have? A Billy Boyle Mystery by James R. Benn.

Benn, a Hadlyme resident, recently spoke at the Essex Library about his latest mystery novel, The White Ghost, which features Billy in a new locale, the South Pacific, and involves another famous family, the Kennedys. Benn builds his plot around John F. Kennedy’s service in 1943 as commander of PT Boat 109, the torpedo patrol boat that was rammed and sliced in half by a Japanese destroyer.

Benn was the first of five authors to speak at the Essex Library this fall. On Thursday, Oct. 8, noted photographer Stacy Bass will talk about her new book Gardens At First Light, photographs of private estates in the Northeast at sunrise. On Tuesday, Oct. 13, author Sam Tanenhaus, a former editor of The New York Times Book Review, will interview novelist Kate Walbert about her new book, The Sunken Cathedral. On Tuesday, Oct. 27, Tanenhaus himself will give a talk on The New York Times Book Review and how it works. Robert M. Dowling, the author of Eugene O’Neill: A Life in Four Acts, will give the final talk in the author series on Thursday, Dec. 3. All lectures take place at the Essex Library at 7 p.m.

The White Ghost is the tenth mystery novel in the Billy Boyle series. Previous adventures have found Boyle in Sicily for an Allied invasion that involved cooperating with both the local and American Mafia, and in Norway investigating the theft of Norwegian gold and in North Africa solving the disappearance of something as valuable to American soldiers as gold: penicillin.

Benn has set all his mysteries in World War II because of his own love of history coupled with the stories his father told him about serving in the conflict. In addition, Benn learned historical mysteries were the fastest growing genre of suspense stories and, when he started, nobody had yet done a series on World War II. Since Billy’s debut, he added, there have been a few other series focusing on the war.

Benn can’t explain where the name Billy Boyle came from; one day it was in his head and he knew it was right.

“Something about the alliteration, maybe,” he said.

Billy, the son of an Irish police detective with an uncle who just happened to be on the promotions board when Billy himself made detective, is a true son of Boston. In the first books in the series, Billy even rooted for the Red Sox. Reality changed that bit of Benn’s fiction when the Red Sox won the World Series in 2004 after an 86-year hiatus. Benn, a Yankee fan, decided he had done enough for the opposition. He changed Billy’s loyalties to the Braves, now long-departed from Boston. That team’s travels have since taken them first to Milwaukee and now to Atlanta.

Benn describes authors as either architects or gardeners. Architects outline and have the plot all worked out before they begin. Gardeners go where the action takes them. Benn is a gardener. He works out his plot as he goes along, changing things as his ideas change. Sometimes people congratulate him because mystery was so intricate they had no idea who the murderer would be.

“Of course, when I started I might not have known either,” he said.

Benn says writing mystery stories is both very similar to writing other kinds of fiction and at the same time very different. He compares it to what Ginger Rogers said about her long dancing relationship with Fred Astaire: She did everything he did, but she did it in high heels going backwards.

Fans of the Billy Boyle series come in all ages. At a recent gathering, one member of the audience who had served in World War II, talked about his own memories of a conflict that had in his lifetime gone from front pages to history books. On the other end of the spectrum, Benn has heard from the parents who say their teenage sons have been turned on to reading by the books.

Benn spent his professional career as a librarian, retiring in 2011 to write full time. He completed his first two Billy Boyle novels without having either a publisher or an agent. In fact, all 200 agents to whom he had sent completed chapters rejected his books. He decided to try one more time, sending out 60 additional letters, but with no more initial success. Then, six or seven months later, just as he was about to leave for a trip to Italy, the phone rang when he was in the shower. It was an agent with a British background who said his description of wartime London was “spot-on.” Ultimately, two publishers expressed interest in the series, all of which have been published by Soho Press.

In addition to The White Ghost, which has just come out, Benn has completed another Boyle mystery on stolen art in occupied France that will be published next year and he is doing the research for yet another Billy Boyle mystery on neutral Switzerland’s relationship with Germany during World War II.

Benn admits he sometimes sees a lot of himself in the detective he created.

“Neither of us liked school much. And he was a wise guy,” Benn said (without admitting whether he himself shared that characteristic).

Billy started as a second lieutenant, then got promoted to captain, but Benn said that he will never make major. In a subsequent book Billy will get busted down in rank.

“He just can’t stay out of trouble,” Benn explained.

Author Lecture Series at the Essex Library

Thursday, Oct. 8, Stacy Bass on Gardens at First Light

Tuesday, Oct. 13, Kate Walbert on The Sunken Cathedral

Tuesday, Oct. 27, Sam Tanenhaus on The New York Times Book Review

Thursday, Dec. 3, Robert M. Dowling on Eugene O’Neill: A life in Four Acts

All Lectures at the Essex Library at 7 p.m. For more information call the library at 860-767-1560 or visit www.youressexlibrary.org.