Meet Art and Mimi Brotherton. Devoted siblings and housemates, they’re bound together by the tragic death of their parents. They agree on not quite everything.

Art thinks people are incapable of making sensible decisions, especially when it comes to love. That’s what algorithms are for.

Mimi knows her brother is a mathematical genius, but thinks maths isn’t the answer to everything.

When Mimi decides she needs more from life than devoting herself to her brilliant brother, she starts looking for love. But Art has a condition: that she find her soulmate using a strict mathematical principle. Initially, things seem promising. That is, until Mimi meets Frank: a romantic, spontaneous stargazer, and also a mathematician. But definitely not algorithm-approved.

As Art’s mistrust of Frank grows, so do Mimi’s feelings, and the siblings’ relationship is tested to breaking point. Something about Frank doesn’t quite add up, and only Art can see it …

The Theory of (Not Quite) Everything by Kara Gnodde is a tender, intelligent and uplifting novel about brothers and sisters, true love in all its forms, and how life is more than just a numbers game …