Who the fuck is this guy? Ed Burns thought after David Simon introduced himself in the winter of 1984. The moment would mark the beginning of a collaboration neither could have foreseen, one that would mature into a groundbreaking book and culminate in a revolutionary television show. But first impressions? Burns joked—well, partly anyway—that he hoped to arrest Simon. Somehow, Simon had finagled his way beyond security and into the Drug Enforcement Administration offices as Burns readied material for a grand jury preparing to bring an indictment against Melvin “Little” Williams, a disciplined drug trafficker who had successfully flummoxed Baltimore law enforcement for years. Simon told Burns that he was a reporter for The Baltimore Sun and had permission to follow the case. Burns and his partner, Harry Edgerton, both Baltimore police detectives, had finally pinned the elusive Williams through the use of a wiretap. Simon expressed interest in being able to listen in on the wire. “I’d love to take you in there, but if I do, that’s a ten-year offense and I’d love to lock you up,” Burns said. He stiff-armed Simon’s request, but agreed to meet with him later to discuss the case.

Who the fuck is this guy? David Simon thought after meeting Burns a second time. Not much time had passed when they greeted one another at the Baltimore County Public Library branch in Towson. Simon had already surmised that Burns did not behave like any typical detective he had come across. He now eyeballed the book titles Burns prepared to check out, Bob Woodward’s Veil: Secret Wars of the CIA and The Magus, by John Fowles, among them. “I read all the time, and it impressed him,” Burns recalled. “I don’t think David reads anywhere near as much as I do, but a cop reads? My God. I know a lot of cops who read. It was no big deal, but David was a good guy and he had a passion.”

That passion unfurled into the canvassing five-part series that Simon wrote on the making and inner workings of Williams as a Baltimore drug trafficker kingpin. For Simon, his life’s purpose had been achieved by working at a newspaper. His father, Bernard, had once been a journalist who devoted the bulk of his working days as a public relations director for B’nai B’rith, the oldest Jewish service organization in the world. His mother, Dorothy, spent time working for an organization that aided students from underachieving public schools to find better education. Simon attended the University of Maryland, where he wrote for the student newspaper, The Diamondback. He joined the Sun after graduating, reporting on crime. To him, being a newspaperman and bringing accountability to influencers meant something. “I grew up in a house where we argued politics,” Simon recounted. “We argued sociology. We argued culture. We argued. It was not personal. Arguing was how you got attention in my family.” One of Simon’s enduring memories is debating politics with his two uncles as a boy, the moment climaxing with him flatly telling his uncle Hank that he was in the wrong. “Who knew he had a brain?” Uncle Hank retorted.

Reading Simon’s 1987 Sun series, entitled “ ‘Easy Money’: Anatomy of a Drug Empire,” is akin to viewing the organs of The Wire’s first-season wiretap investigation. Williams was a self-made entrepreneur who imported the bulk of Baltimore’s heroin influx as the city’s honest economic opportunities shifted and dwindled. “An imperious, intelligent man who chooses words with care,” Simon described “Melvin Williams refuses to be stereotyped. Street sales of narcotics were routinely punctuated by murderous violence, but Williams was a family man, devoted to an eleven-year marriage and two young daughters.”

Williams conducted most of his business through his number two, a consigliere named Lamont “Chin” Farmer. Farmer orchestrated both a simple and intricate communication system involving the use of beepers. He also headed a print shop and took business courses at a community college, à la Idris Elba’s Stringer Bell.

Simon’s series meticulously captured Williams’s life and downfall—not only as a drug kingpin, but also as a respected figure in the community, where, as Simon wrote, “he was hailed as Little Melvin, the Citizen, speaking at the request of National Guard officials during the 1968 riots, urging a restless crowd to go home.” Burns appreciated that Simon showed all facets of the case and offered a depiction of Williams that was beyond a caricature. “When the case came down, he wrote a very good article because he went out and saw some of the gangsters and it was a most balanced article,” Burns said. “I liked that.”

Simon spent Christmas Eve 1986 on an overnight shift with the Baltimore Police Department Homicide Unit for another story shortly before the series on Williams debuted. During that night, a detective mentioned that someone could write a damn good book if they documented the department’s happenings for a year. With the permission of Police Commissioner Edward Tilghman, Simon gained complete access to be a fly on the wall with the unit, despite the objections of some of the department’s personnel. “A captain had a vote,” said Jay Landsman, then a homicide detective sergeant, who also lent his name and acting abilities to The Wire. “He took a poll of who wanted to do it and who didn’t. Twenty-eight out of thirty of us, including myself, voted against it. We worked murders in the ghetto. You lived in a gray area with that. It doesn’t always look pretty. Everything we did was legal, but it was kind of how were they going to interpret it? So, naturally, since they had a democratic election and we all voted against it, they gave him the go-ahead.”

Simon took a leave from The Baltimore Sun, becoming a “police intern” in January 1988. Members of the department playfully hazed him until he proved game for the task. He gained enough insight into the minds of the squad members that some later acknowledged that he had accurately captured words and feelings they had never verbally expressed. Houghton Mifflin published Homicide: A Year on the Killing Streets in June 1991. The book, like the series on Williams, is peppered with scenes later extracted for The Wire. In it, Simon provides a penetrating portrait of how the detectives attempted to unravel murder cases and the humanistic toll it took on them. “It was daily that we told him if he printed anything we didn’t like, we would kill him,” Landsman said. “But he grinned at everything. As it turns out, we weren’t as bad as we thought we would be portrayed by David.”

Ed Burns, working another prolonged investigation, scarcely figured into the book. He was already grappling with the limits of how little one outside-the-box thinker could influence a lurching institution. “We were like family,” Landsman said. “But [Burns] was the biggest pain in the ass in the world. He once said everybody in police should have a bachelor’s or master’s degree. I said, ‘Then we’d all be like you. That would be hell, because you’re an asshole.’ It was all in fun, but he played to his own drummer. When you really needed something done, you had to just put your foot down on it. But he was tenacious as hell, a little bit gullible. Like that informant Bubbles that he had. I wouldn’t believe Bubbles as far as I could throw him. A broken clock is right at least twice a day, and I guess that’s the two times he gave Burns good information.”

Burns left the police force, having knocked his head against his superiors for much of his two decades as a patrolman, plainclothesman, and detective. He was about to start his new life as a middle school teacher when Simon proposed a collaboration. Simon’s book editor, John Sterling, suggested that the proper follow‑up to Homicide would be observing a drug corner in Baltimore for a year and depicting the story’s previously undocumented other side of addicts. Burns agreed to contribute, and the two settled on the intersection of West Baltimore’s Fayette and Monroe. For weeks, Burns spent his days gaining the confidence of dealers and users, while Simon worked at the newspaper before taking a second leave. “The badge can get you under that yellow tape, but it can’t get you into their shooting galleries and places like that,” Burns said. “I could sit down on the third floor of a shooting gallery with five or six guys pumping all around me, a prostitute working out in the bed over there, and have a conversation. Every once in a while, they take the syringe off [from behind] their ear, get a little hit, put it back on, and it would be a conversation where you knew that these people were aware of what was going on and how they had been sucked into this trap.” As he had in Homicide, Simon displayed a perceptive ear in deciphering the corner’s dialogue. He had to learn the appropriate jokes to laugh at, when to show concern, when to blend in, or when to pop up with a question. Homicide was heavily saturated with cop jargon—a red ball, a whodunit, dunkers. The Corner: A Year in the Life of an Inner-City Neighborhood was published in 1997 and introduced the reader to a new vocabulary, with words such as testers, the snake, and speedballs. The piercing narrative focused on the McCullough family and their efforts to function as a unit even as they dealt with the toll drugs extracted from them. Gary McCullough, the father, had been a businessman who fell into the throes of addiction once his marriage to Fran Boyd crumbled. Boyd, also addicted to drugs at the time, still tried mapping a better life for her sons. They included DeAndre McCullough, who, at the age of fifteen, had already begun peddling drugs. (DeAndre would go on to work on the set of The Wire and portray Lamar, Brother Mouzone’s dim associate, before his death at the age of thirty-five in 2012.) Some,...