The subtitle “A Bob Lee Swagger Novel” tells readers all they need to know about the quality of the story that awaits them. It would be tough --- maybe beyond my limited abilities --- to tell you how happy I am to see those words on the cover of Stephen Hunter’s latest effort. Bob Lee Swagger, the Marine sniper known as “Bob the Nailer,” is now past the age of 70, and while the spring in his step may be a bit less functional, it is certainly up to any job that comes his way. G-MAN ultimately demonstrates this in a first-rate tale that spans decades and generations.

The book opens with an unexpected discovery that occurs when the Swagger homestead, having been sold to a real estate developer, is being demolished to make way for a new subdivision. A strongbox hidden in the depths of the house is found to contain a number of cryptic items, including a handgun; a thousand dollar bill, deliberately preserved with great care; a crudely drawn map; and a machine part that is unidentifiable yet somewhat familiar. The objects date back to the mid-1930s, the time of Charles Swagger, Bob’s enigmatic grandfather.

"Those who grew up watching 'The Untouchables' or the plethora of gangster films that were made in the early and mid-20th century will find much to love here, not the least of which is Hunter’s penchant for historical accuracy and firearms lore."

Bob knows little about Charles, other than that he was a veteran of World War I and the high sheriff of Polk County, Arkansas. Charles was, from all accounts, a quiet and taciturn man, of whom Bob’s father, Earl, barely spoke. When Bob is advised of the discovery of the long-concealed box, he uses it as an opportunity to investigate his own heritage while attempting to unravel the secrets of the objects in hopes of discovering the essence of his grandfather, who apparently died under a cloud of suspicion after a career as a respected law enforcement officer.

The narrative of G-MAN thus alternates between the past and the present. In the present, Bob returns to the family homestead and begins to doggedly research Charles’ life and career. It is not an easy task. Charles eschewed publicity, choosing to do his job quietly and with an astounding but matter-of-fact competence. Bob also slowly but inexorably discovers that someone seemed determined to conceal Charles’ actions in the 1930s. We learn that in 1934, Charles, whose reputation preceded him in law enforcement circles, was secretly recruited to serve in the Division of Investigation --- later to become known as the Federal Bureau of Investigation --- in their Chicago office, in order to bring down a cadre of notorious bank robbers.

Charles quickly establishes himself as a first among equals in the office, where his limited education in an office full of men with college degrees is more than compensated for by his extensive knowledge of and experience with firearms, and his tour of duty in the Great War. The Division quickly sets its focus on a notorious criminal named Lester “Baby Face Nelson” Gillis, an extremely impulsive, violent and dangerous fugitive from justice who has been robbing banks across the Midwest. A third narrative thread follows Gillis, who is bent on accomplishing one last major robbery in order to facilitate his retirement and enjoy life with his wife and children. But the Division in general and Charles in particular seem to magically thwart Gillis at every turn, methodically eliminating his associates. Gillis suspects treachery on the part of someone in his organization, and he may be right.

Meanwhile, in the present, Bob gets the sense that someone seems to be tracking his every move as well. He is correct. Hunter lets us in on the “who” and the “why” as he moves grandfather and grandson along their respective time periods. Revelations abound for both, as Charles, some eight decades in the past, relentlessly pursues the cold-blooded Gillis while battling an internal demon or two of his own, and Bob in the here and now attempts to solve the enigma that was Charles, determined to arrive at the truth even though it may be unsettling, or even devastating.

Hunter initially doesn’t seem to be in any particular hurry to move the tale along, either in the past or the present. But move it does, almost of its own accord. The pages fly by once the introductions are made and the characters are in place. Those who grew up watching “The Untouchables” or the plethora of gangster films that were made in the early and mid-20th century will find much to love here, not the least of which is the author's penchant for historical accuracy and firearms lore. This combination makes G-MAN one of Hunter’s best works to date, which is certainly a major feat.