Like circles of a Venn diagram, Mimi and Art Brotherton have always come as a pair. Devoted siblings, they're bound together in their childhood home by the tragic death of their parents.

Art believes that people - including his sister - are incapable of making sensible decisions when it comes to love. That's what algorithms are for.

Mimi knows that her brother is a mathematical genius. But she believes that maths isn't the answer to everything. Not quite. Especially when it comes to love.

Still, when Mimi begins her search for a soulmate, Art's insistence that she follow a strict mathematical plan seems reasonable. The arrival of Frank, however - a romantic stargazer who is definitely not algorithm-approved - challenges the siblings' relationship to breaking point. As their equilibrium falters, Art's mistrust of Frank grows, but so do Mimi's feelings. 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 . . .