Every now and then, a book comes along that everybody seems to be talking about — even if it isn’t exactly “new.”

At the moment, one such title is Project Hail Mary, the latest from Andy Weir — whose The Martian scored big on both page and screen some years ago.

Almost every time I mention Hail Mary, someone responds, “I loved it!” … or “I’m reading that now!” … or “It’s on my ‘next’ list!” (One friend told me he’d so often resolved to read it that he wound up buying two separate copies.)

Originally published in 2021, Weir’s dazzling masterpiece enjoys nearly 100,000 five-star reviews at Amazon; it is still listed as that site’s top seller in “Space Opera Science Fiction.”

I ranked this book among my all-time sci-fi faves even before I’d finished it; but to be honest, I’m loath to reveal any details about the plot, which starts off promptly with “What’s two plus two?”

The narrator does not know the answer — and the book gets instantly interesting as he tries to figure out why he doesn’t know, and where he is, and what he’s supposed to be doing there.

Since I’ve already mentioned science-fiction, I suppose I can explain that PHM ultimately concerns a space-mission to save the human race.

Along the way, Weir gets wildly inventive with microscopic creatures that seem bound to destroy all life on earth — and a whole lot more that I’m not gonna tell ya.

Suffice it to say that Project Hail Mary boasts a careful plot-structure in which the narrator’s nonstop problem-solving alternates with flashbacks to earth explaining the background that he gradually starts to remember.

But while Weir’s tale is rife with the intoxicating invention and imagination that characterize the best SF, he likewise keeps it firmly grounded in science.

Indeed, if the book has a flaw, it’s only that it sometimes gets too bogged down in technical mechanics — involving light-speed, gravity, atmosphere, a plethora of chemical elements and a whole lot of math.

Yet somehow, Weir is able to make all this pretty clear for novices and non-geeks (though as both a sci-fi fan and a word-specialist for Webb, I can’t pretend I’m not a geek!).

Yet at the same time, for all the complex calculation and terminology, it’s also an intensely human book — with touching development of the narrator’s new and old life, and a truly groundbreaking take on friendship.

Weir also has a seemingly boundless capacity for plot twists. And so, between this, and the mystery, and the flashbacks, and various life-and-death crises that arise, the book is a genuine page-turner.

One other feature worth mentioning: PHM is relatively free of salacious material like violence, obscenity and sex. (If I recall correctly, it has only 2-3 strong swear-words and about one page of innocuous sex-talk.)

And then to cap it all off, Weir somehow manages a finale that’s both open-ended and supremely satisfying — a feat which is, in my reading experience, nearly impossible to pull off.

Happily, PHM is now in development as a movie, with the same writer as Ridley Scott’s The Martian — and a cast that headed by Ryan Gosling.

In the meantime, even folks who don’t care for sci-fi are likely to enjoy this gem. Strongly recommended for book groups!