The Humans by Matt Haig
Saw the author tweet about this book and it looked good, so I bought it. Proof that marketing on Twitter does work.
Very quirky and enjoyable novel. The narrator is an unnamed alien, who has taken the form of maths professor Andrew Martin. He's been sent to stop the humans finding the proof to the Riemann Hypothesis (you don't need to know what that is) because if they do, it'll unlock all sorts of knowledge to them (us) and they (we) are not mature enough to handle it properly.
The alien is supposed to find out who knows what the prof discovered, and then kill them all including the prof's wife and son. Sounds bleak, doesn't it? But actually this book is funny and warm, and says a lot about what it means to be a human, as the alien gradually learns more about this odd species with its emotions and passions and desires.
A short book and highly recommended. If Dad had still been with us, I'd have passed my copy onto him, knowing he would love it.