The easiest way to describe the Tripods Trilogy is to say it's a re-imagining of War of the Worlds, but with the aliens triumphing over mankind instead of dying because of a bunch of pesky germs. As alien invasions go, the overlords in the series are pretty benevolent at first. The aliens limit their presence to three domed cities and routine patrols by towering, three-legged machines known as Tripods. Humans live semi-autonomously in peaceful agrarian villages and small cities. War and disease are a thing of the past.
It's not exactly an ideal setup, however. The aliens saddle all humans with mesh caps to inhibit their brain activity at the age of 14. The process halts free thought in its tracks, keeping technology stalled at a level where the clock is the most advanced invention. The world's greatest cities lie in ruins. And it soon becomes clear that the alien "Masters" aren't as kind as they might seem.
Christopher (the pen name for writer Christopher Youd) never talks down to his readers, meaning the books are an enjoyable read for both adults and teens. The advanced vocabulary, not to mention the fact that the trilogy was penned by an English author, might prove a little daunting to young American audiences. I gave up on the series when I first tried it out, but devoured the books in the course of a week when I picked them up again.
The first book, The White Mountains, follows a group of boys as they undertake a dangerous journey to join an anti-Tripod resistance movement in the Alps. This is followed by The City of Gold and Lead, which focuses on a resistance effort to infiltrate one of the alien cities. The trilogy concludes with The Pool of Fire and a climactic effort to defeat the Masters and regain human independence. Christopher wrote the prequel some time later to clarify the question of how the Tripods managed to take over the world.
The books carry on a spirited adventure story, from the pleasure of wandering the countryside with friends to life-or-death battles against a powerful enemy. But the trilogy isn't just a dime store yarn. Christopher packs the narrative with a number of substantial themes to reflect on. The protagonist questions whether society is any worse under alien control, a theme reflected in Christopher's query on how well humanity can cooperate, Masters or no Masters.
The trilogy was written in the 1960s, and to some extent it's a product of its time. This blogger, writing an entry on Christopher's death in 2012, notes how the handful of female characters who appear in The White Mountains generally present obstacles to the boys' efforts to join the resistance. No women at all show up in the next two books. There's also a certain amount of casual racism, in particular Christopher's reference to the "little yellow men" who lead a resistance movement in Asia.
The Tripods Trilogy was popular enough that it spurred a BBC series, but this petered out before it ever reached a conclusion. There has been buzz about bringing the trilogy to the big screen for years, but unfortunately this hasn't amounted to anything. But the books are a memorable experience for anyone who comes across them, and a fast enough read to complete in a few dedicated sessions. Read them with War of the Worlds for the full Tripod invasion experience.