After Cambridge mathematician Andrew Martin proves the Riemann Hypothesis, he is replaced by an alien whose job it is to prevent news of the discovery from spreading as it is their belief that humans are not yet ready for the power it would afford them. The alien doppelganger surprises Martin's family and colleagues by being seemingly more human than the emotionless mathematician ever was, and they surprise him by being more worthy than the primitive creatures he had been led to expect.
Of course, there is no reason to think that a proof of the Riemann Hypothesis would actually have any dramatic impact on the human race. Haig's claim that it would imply the existence of a "pattern" for the "first hundred thousand or so primes" is inaccurate, probably a misunderstanding based on the conjecture has been checked for the first hundred thousand or so primes. In fact, as you can read about in greater detail here, the Riemann Hypothesis is the conjecture that the zeroes of a certain function that can be written in terms of the prime numbers are all either negative integers or complex numbers with real part equal to 1/2. Of course, it is possible that a proof that this is true would provide knowledge that could have some important consequences that we cannot yet imagine, but I would not want anyone to misunderstand and suppose that this question, intriguing as it is to mathematicians, is necessarily of great importance to anyone else. The only immediate consequence I know of for the Riemann Hypothesis itself, which would not excite anyone but an expert number theorist, is that a certain known approximation to the function that counts the number of primes less than a given number would be known to be a slightly more accurate approximation than it might otherwise be. Hardly an application of Earthshattering consequences.
But, then, the mathematics is not really the main focus of the book. Told from the point of view of the alien who has taken over Andrew Martin's life, it is his growing appreciation of humanity and the things we have made (from peanut butter to pop music) that seems to be the key point.
Contributed by
Hauke Reddmann
You are no true bibliophile if it hasn't happened to you that you wander through a
library and a book cries "Read Me!" Maybe it's your subconscious recognizing the author.
Matt Haig...who was Matt Haig again? (Author of "The Radleys", which I have read.
BTW, "The Radleys" also is about aliens and alienation, for fuzzy values of "alien".)
"The Humans" is about a bit
of math...and la condition humaine. Which can be succinctly summed up as "full of manure".
No wonder that some panicking aliens decided to stall human progress by taking over
a math professor who proved the Riemann hypothesis and wiping out this fact thoroughly.
Unfortunately, they DidntDoTheResearch. Not so much that humans go clothed (as the finer details of
human customs could take years to make an alien be able to walk unnoticed among us)
but rather HumanityIsInfectious  trying to adapt, the alien quickly discovers
the nicer things of humanity, like Emily Dickinson poems and peanut butter sandwiches,
and slowly becomes human, interfering with his Terminator purpose.
The afterword of the author says that (simplifying a bit) it was either suicide or
writing this book. We are thankful that he choose the latter. A truly human book.
(Oh, and I recommend "The Radleys" also.)
A quick note on the math: It's just a McGuffin. Surely, a physicist inventing
interstellar travel would have been a far more convincing danger for aliens. But
then, a math professor makes a much more convincing alien (resp. an alien a
math professor), thus I won't criticize the author on that point :)

