Bosch investigates a twenty-year-old cold case. Back in 1992 during the Rodney King riots, Bosch and Jerry Edgar were called out to investigate a dead woman found in an alley. The dead woman turned out to be Anneke Jespersen, a Danish journalist in the city to cover the riots, who was found shot through the eye. Unfortunately, due to the orgy of violence and destruction in the city at that time, Bosch and Edgar had to leave the scene after only a few minutes, but not before Harry collected one shell casing from the scene.
Fast forward 20 years. The shell casing found from the Jespersen crime scene is matched with shells and bullets recovered in two other murders, one of which resulted in a gang member going to jail. Bosch, still working in the Open-Unsolved unit, takes the case. He finds a surprising new direction to the case, discovering that the Jespersen murder was not a random crime committed during the riots but a premeditated murder with a motive that dates back years.
Despite the title, does not contain an example of the trope Black Box.
This novel contains examples of:
- Badass Grandpa: Bosch is nearly sixty years old and facing mandatory retirement.
- Bond Villain Stupidity: Discussed Trope, as Bosch can't fathom why Drummond doesn't simply kill him. Finally he figures out that Drummond wants to pin all the murders on Bosch and thus has to keep him alive until some time after everyone else is dead.
- Call-Back: Bosch tells a funny story about when he was a beat cop. The old cop he was walking the beat with would write out traffic tickets for any motorist that heckled them. When Bosch objected that it wasn't in policy, the beat cop said "It's in my policy!" The Call Back comes at the end, when Mendenhall from IA sees that Bosch is going to try and shoot Drummond out of his helicopter, and this same exchange takes place.
- Chekhov's Gun: Several mentions of a wind turbine on the Cosgrove estate, which acts as a power generator. At the climax Drummond flies his helicopter right into the turbine.
- Chekhov's Gunman:
- The National Guardsmen who met Bosch at the scene of the Jespersen murder in 1992 are the bad guys. Drummond, the guardsman who leads Bosch to the body, was the one who killed her.
- Then there's Detective Mendenhall of Internal Affairs, whose appearances in the story seem to be the umpteenth "IA up Harry Bosch's ass" subplot. That is, until she shows up at the climax and saves Bosch.
- Continuity Nod:
- Harry goes to visit the grave of the boy whose murder he investigated in City of Bones.
- Harry commiserates with a fellow cop about former LAPD detective Frankie Sheehan, Bosch's old parter, agreeing "shame what happened to him." This is a reference to Sheehan's death in Angels Flight.
- Bosch remembers how Chief Maycock and his old partner and friend Kiz Rider manipulated him in order to take down Irvin Irving. This is the plot of The Drop. He hasn't spoken to Kiz since.
- Conversation Casualty: Drummond the criminal mastermind and Banks his Mook have tied up Bosch in the barn. Banks, calling Drummond by his old National Guard nickname of "Drummer", asks why Drummond wanted to hide Bosch's car. Drummond says "Reggie, I told you not to call me that," and shoots him in the head. Bosch is shocked not only at the murder, but how Drummond didn't even look at Banks, instead keeping his eyes on Bosch the whole time.
- Cowboy Cop: What does Bosch do, when he's told to slow down on the Jespersen investigation? He takes vacation so he can investigate the crime on his own. This nearly gets him killed.
- Da Chief:
- O'Toole, Bosch's new lieutenant, is a political animal who is only too eager to shut Bosch's investigation down.
- The chief of police himself, Martin Maycock—the first LAPD chief in the Connelly canon to get a name—who tells Bosch directly to slow down the Jespersen investigation.
- Distant Prologue: The opening scene is set in 1992, and recounts Harry Bosch's rushed, cursory investigation into the Anneke Jespersen murder. Then the story jumps forward 20 years and picks up with Bosch in the Open-Unsolved unit going back to the Jespersen killing.
- Double-Meaning Title: The Black Box is both the box holding the information that cracks a case, and death.
- Fun with Acronyms: Community Resources Against Street Hoodlums.
- Internal Affairs: For once, not only does Bosch finally encounter an honorable Internal Affairs cop, said IA cop winds up bailing Bosch out of a jam.
- Internal Homage: The title of The Black Box is a shout-out to the beginning of the Harry Bosch series, the first two novels of which were The Black Echo and The Black Ice. Connelly begins the novel with a thank-you to readers for keeping Harry alive for 20 years and the story begins 20 years in the past, with the initial call-out for the cold case Harry investigates in the story.
- Missing White Woman Syndrome: This is discussed more than once in regards to the victim, a white lady reporter killed during the 1992 Rodney King riots. LAPD does not want to give the impression that they are driven by the Syndrome. Management's resistance to Bosch pursuing the case is driven by Chief Maycock's fear that the department will look bad if the only murder from the riots that they solve is that of a white woman.
- Moe Greene Special: The victim is shot right through her right eye.
- Pink Mist: "Bosch was hit by the blow-back of blood and brain matter a split second before Banks's body dropped to the hay-strewn floor next to him."
- Real Person Cameo: Real-life LAPD detective Rick Jackson is a co-worker of Bosch's and accompanies Bosch to his hearing with Internal Affairs.
- Thanking the Viewer: The Black Box has an opening dedication thanking readers for keeping Harry Bosch alive for 20 years.
- What You Are in the Dark: Bosch is sorely tempted to execute a grievously injured Drummond after Drummond crashes his helicopter. But he doesn't.