Agent Z is a fictitious character in a series of four comical children's books written by British author Mark Haddon, better known for his 2003 novel The Curious Incident of the Dog in the Night-time. In the first published versions of the books Haddon also did the artwork for the covers and a number of illustrations inside (the cover pictures were changed for later editions). The Agent Z series is set in the present day in an unnamed British city.
Agent Z is not an actual living person in the books but a 'front' used by three schoolboys, Ben, Barney and Jenks, who have been friends for years, and who also call themselves the Crane Grove Crew. The mission of Agent Z is to wreak havoc on the unsuspecting and the deserving in a battle against boredom. The missions take the form of practical jokes, and with the culprits usually leaving a Z mark (like Zorro) on the scene of the prank. The Crane Grove Crew have their own secret base in a boarded-up, derelict park-keeper's cottage on the edge of the park near where they live. With a few exceptions that emerge in the stories, no-one knows of the identity of Agent Z, and the boys say they have made a pledge of secrecy never to reveal the identity of Agent Z.
In 1996 Agent Z and the Penguin from Mars was adapted for television by the BBC.
The three main characters are 12-year-old boys.
The Crane Grove Crew keep a record of their practical jokes on a wall in their Command Centre. They also rate each one on a scale of 1 to 10 in accordance with the criteria 'Daring', 'Success' and 'Laugh Value'. The only clues to the nature of the operations are the Z stickers left at the scene of each attack. Among their many practical jokes:
The Crane Grove Crew use a secret code language known as Pig Latin, which involves simply shifting the first letter from every word and then adding that letter to a suffix 'ay' that follows the word: Thus, the word ‘Ready’ becomes ‘Eady-ray’; ‘Done’ becomes ‘One-day’ and ‘Yes’ becomes ‘Es-yay’, etc.
Barney, Ben and Jenks are already mates, the 'crew', but it seems as if Barney and Jenks are keeping something from Ben. How come, when he went to change back into his shoes after football his shoes were all of a sudden too small, but there was a Z carved in the bottom of them, and how did worms get into the bottom of his bed? No point asking. So next time Ben turns up at the Command Centre he has a box of chocolates with him, something he knows the others can't resist; only it turns out that some of them are filled with mustard – and the box lid is marked with a Z. Ben has got revenge, and in doing so is welcomed as a new Agent Z member. So Agent Z starts playing pranks at school, but one of the victims is Fisty Morgan, the school bully. At first he doesn't suspect Ben, Barney and Jenks, until that is he discovers an Agent Z badge under the Jencks' jacket lapel. The brawl is broken up by new teacher Mr. Forsyth. It materialises that Fisty has been extorting money from other children. He ends up getting suspended from school. But Mr. Forsyth wishes to teach Ben, Barney and Jencks a lesson too; and thus gets them to clear his garden at the weekend. But they get revenge, by fixing kippers to the underside of his car; he and the car end up reeking of fish. But the glorious victory is short-lived when someone calling himself the Masked Crusader appears one evening from nowhere at their command centre. After an initial panic the boys manage to lock him in, only for him to escape through a window, and hobbles off. Next day Mr Forsyth has a noticeable limp. He surely is the Masked Crusader. They offer to call a truce and give him an Agent Z badge, as an "honorary" member of the crew.