A reprint paperback of Terry Pratchett's Johnny and the Bomb, the latest installment from the Johnny Maxwell series, will be available in April. This is a story about a group of accidental time-travelling teenagers "lost in the trousers of time." They are unexpectedly transported back to the year 1941, with the knowledge that the small town in which they live was bombed on that very day during World War II.

The teens are faced with many dilemmas:

• Should they intervene to save innocent lives, or will taking action change the future that they know?
• If they do intervene, how could they convince people to take action?
• Will they figure out how to return to their own time, or will some of them remain stuck in the past, far from the family, friends, and video games they love?

The characters in this story are funny and lovable, from the seemingly ordinary Johnny, whose mind is the only one among his peers who can accept the intricacies of time travel, to the slightly askew time bag lady Mrs. Tachyon.

Just as Madeleine L'Engle attempts to explain the Tesseract in the Wrinkle in Time series, Terry Pratchett also expends effort describing time travel in a way that teens or older kids can understand. He uses the following analogy to describe the theoretical alternate realities that might occur:

"Did you know that when you change time, you get two futures heading off side by side? ...Like a pair of trousers."

In typical Pratchett style, he also exhibits a slightly lopsided sense of British humor to describe the world and the people in it:

"Garn! Say something American!"

"Er... right on. Republican. Microsoft. Spider-Man. Have a nice day."

This demonstration of transatlantic origins seemed to satisfy the small boy.

My only criticism is that, though this children's book is targeted at an audience of kids ages eight and up, perhaps some of the time travel and cognitive dissonance theory eluded to is a bit intellectual for kids in the lower end of that age spectrum. Perhaps that is my own inaccurate assumption though. I'd like to hope that Pratchett is on target, and that kids are ready to absorb the varied nuances of such intelligent science fiction. He does use language and metaphors geared towards the appropriate age level, and readers will likely still enjoy the action and humor even if they do not grasp the complexity of time travel theory.

Terry Pratchett is the author of the bestselling Discworld series for adults — tales of a flat planet with a mix of hilarious characters and their fantastical adventures.