
Discworld
fantasy
Series · fantasy
The Johnny Maxwell Trilogy series by Terry Pratchett has 3 books and is best read in publication order, starting with Only You Can Save Mankind (1992).
Start here: Only You Can Save Mankind (1992) — then read straight through in publication order.

The order the books were released — the default way to read the series.
Johnny Maxwell is an ordinary, slightly odd teenager in an unglamorous English town whose life keeps intersecting with things that shouldn't be possible. In Only You Can Save Mankind (1992), Johnny discovers that the alien fleet in his video game is asking him -- specifically him -- to negotiate a ceasefire, forcing him to reckon with the fact that he's been mindlessly slaughtering sentient beings for entertainment, all while the real-world backdrop of the Gulf War plays on the news. It's one of Pratchett's sharpest satirical premises, using a kid's video game as a lens on real war.
Johnny and the Dead has Johnny befriending the residents of a condemned local cemetery, who need his help to stop their graveyard being sold off for redevelopment, while Johnny and the Bomb sends him and his friends back in time to a WWII bombing raid via a homeless woman's supermarket trolley, grappling with the ripple effects of changing the past. Across all three, Pratchett grounds fantastical premises in a recognizably mundane, working-class English setting, using comedy to approach real grief, war, and social neglect.
Read in publication order: Only You Can Save Mankind, Johnny and the Dead, Johnny and the Bomb. Each book is a self-contained adventure with its own premise, connected only by Johnny and his friend group, so you can technically read them independently, but publication order lets you watch the characters and Pratchett's handling of them mature across the trilogy. No Discworld knowledge is needed.
Three: Only You Can Save Mankind (1992), Johnny and the Dead (1993), and Johnny and the Bomb (1996).
Publication order: Only You Can Save Mankind, Johnny and the Dead, Johnny and the Bomb. Each is a self-contained story, so strict order isn't essential, but it's the standard reading sequence.
No -- it's set in the contemporary real world (with fantastical intrusions), unrelated to Discworld.
A teenager discovers the alien spaceship fleet in his video game is asking to surrender rather than be destroyed, forcing him to confront what mindless in-game violence means -- set against the backdrop of the real Gulf War.
Yes -- like the Bromeliad Trilogy, it was written and marketed for a younger audience, though it handles genuinely serious themes like war and mortality.
Reading order last verified .