Only You Can Save Mankind is the first book in Terry Pratchett's Johnny Maxwell trilogy. While this is considered juvenile or young adult fiction, it's a lot of fun for adults as well. It seems a little strange to journey with Terry Pratchett to a place other than the Discworld, but this little jaunt is quite enjoyable. Johnny Maxwell is a rather typical twelve year old boy; he's not smart or popular or rich, and he tends to prefer operating below the radar of those around him. He is living in Trying Times, basically having to take care of himself for the most part while his parents argue and come ever closer to splitting up. Like any kid, he enjoys a good computer game every now and then, and his friend Wobbler, born to be a hacker, supplies him with just about any illegally pirated game he could want. As earth's last remaining fighter, he has destroyed all but the last big alien ship in the game Only You Can Save Mankind when a message suddenly appears on the screen: We wish to talk. Thus begins a journey that takes him inside the game as the Chosen One, the human who will lead the alien ScreeWee race back to safety beyond The Boundary. The reptilian captain of the ScreeWee is tired of fighting; the human fighters appear out of nowhere, kill and destroy ships in her fleet, and keep coming back no matter how many times they are killed. She has seen what happened to the Space Invaders and would rather surrender than die fighting.
You don't have to remember playing Space Invaders to enjoy this book, but it does make the story a little more enjoyable. As always with Pratchett, the characters are well-developed and quite remarkable. I really liked Wobbler, the future hacker who designed a game of his own called Journey to Alpha Centauri to be played in real time, meaning all the thousands of years it would take to reach Alpha Centauri is how many years the game would take you to actually finish it. Beyond the comedy present in this story, there is also a message. The backdrop of the earth-based events of the book is the Persian Gulf War, and the juxtaposition of this war that is real but seems like a game with the computer game that becomes real for Johnny Maxwell conveys a message about violence and one's attitude toward it. It is not an overbearing theme, but it is there to some degree, helping make this short novel much more than just a juvenile read intended to entertain the reader and nothing else. This is a short book that never falters from beginning to end, and it houses much more in its pages than might be apparent at first glance. It is not as complicated or brilliant as the Discworld novels, but it is a fun read nonetheless, sure to entertain Pratchett fans while capturing the attention and interest of young readers.