I saw this book on the library shelves for several weeks before I decided to give it a read. That’s because I was so disappointed by Weir’s second novel, Artemis. Weir’s first novel, the one that catapulted him to international literary fame, was, of course, The Martian, which was turned into a major movie that received numerous awards and accolades. I never read The Martian, but I watched the film several times. On the strength of that story, I read Artemis, which is entertaining but ultimately a disappointment. The main character is unsympathetic; she is a petty smuggler who is willing to sabotage expensive industrial equipment just so she can improve her living conditions.

In Project Hail Mary, Weir returns to the perspective and focus that made The Martian such a hit: an emphasis on science, or at least pseudo-science, as the hero that saves the day. In The Martian, stranded astronaut Mark Watney must use his scientific knowhow to learn how to survive on Mars until he is rescued. In Project Hail Mary, the stakes are far greater. The fate of the entire planet is at stake. A single-celled space creature has begun to feed on the sun’s energy, and first-person protagonist Ryland Grace must figure out a way to stop the invading pests before the Earth and the rest of the solar system freezes. To accomplish this, he is sent on an interstellar mission to the Tau Ceti system; Tau Ceti is the only nearby star that has not been infested by the space plague, and he and his crewmates need to find out why. However, to complicate matters, when Grace arrives at his destination, he wakes up from a four-year coma with amnesia, and his crewmates are dead. Lo and behold, though, an alien ship has arrived in the system with a sole survivor and the same mission. Grace slowly recovers his memory in flashbacks that provide back-story. He also learns to communicate with the alien, a spider-like creature without eyes but with a heightened sense of hearing, and together they set about working together to save their respective worlds.

This all sounds wild and complex, and it is, but Weir makes it exciting, poignant, and credible with his emphasis on hard science supplying the answers to the innumerable crises that pop up one after the other. Grace is a scientific and mathematical genius, and his alien ally, whom Grace nicknames Rocky, is an engineering whiz. Their skills complement each other as they unravel the mystery of what the space plague is and how it can be defeated.

This all makes for a lot of fun and adventure. In fact, Project Hail Mary is the most entertaining hard science fiction novel I have read in a long time. I don’t know enough science or math to know whether Weir’s explanations make any sense, but they have verisimilitude, and that’s the important thing in a story like this. Of course he is making it all up, but as far as I can tell, he is using as much real science as he can in the process. It’s a lively read, and one of the great things about it is its escapism; it takes us off this planet to a faraway place where a lone human and his lovable alien sidekick attempt to rescue worlds from oblivion. If I have one qualification to my praise, it is that for me Weir throws in a few too many crises at the end. Everything that can possibly go wrong does go wrong, one thing after the other, and the hero Grace must use his ingenuity over and over to figure out the problems and come up with solutions. I kept thinking that finally they’ve done it; they’ve saved the day; and then something else comes up. But even these seemingly tacked-on crises are well-presented, exciting, and fun.

Weir is not a stylist. His prose is simple and direct, but that’s the approach that is needed in a novel in which the characterizations are subservient to the ideas. If you take it on its own terms, this is a terrifically entertaining novel. Highly recommended.