A novel with the word ‘theory’ in the title suggests three things to me. First, it’s going to be grim. Second, you’re going to be battered about the head with big ideas. Third, the writer takes themselves very seriously indeed. Yet, as a title, A Theory of All Things is beguiling enough, the bathos of ‘all things’ suggesting there’s going to be some spirited good fun along the way. This book deals with grim stuff, but is itself very far from grim. There are plenty of big ideas, but precious little battering. I very much doubt Peggy Leon takes herself all that seriously. And the good fun is abundant.

I won’t bother summarizing the plot. It hardly matters. The author tells it so well, she could recount the telephone directory and make it interesting. Suffice to say that it’s a story of a family coming apart in order to come together and that the book’s central metaphors are drawn from theoretical physics, notably String Theory. I know two things about String Theory. First, insofar as I understand it, it is one very long conditional. Second, its proponents claim there are ten or eleven dimensions. So here are eleven Ifs concerning A Theory of All Things.

1. If you didn’t know the Big Bang could be darkly funny, unbearably poignant, and elucidate emotion all at the same time, buy this book.

2. If you never thought allusions to Quantum Mechanics could have you weeping with laughter, buy this book.

3. If you haven’t comes across the comic possibilities of ‘interferometers’ or a glorious word like ‘gluon’, buy this book.

4. If you fancy a Feydeau farce for the Internet age, buy this book.

5. If you’re seeking a better illustration than Forster furnished for his famous dictum, ‘only connect’, buy this book.

6. If you’re interested in discovering more truths about vagabondage than Kerouac ever knew, buy this book.

7. If you’re attracted by the idea of a celebration of a dysfunctional family that Tolstoy really needed to read, buy this book.

8. If you care to know what Jane Austen would be writing were she alive today, buy this book.

9. If you want plastic arts portrayed in prose so lucid that you can virtually see the objects hovering above the page, buy this book.

10. If you need a story so happy and so sad that it reminds you why nearly everything in life is of value, the sorrow as well as the joy, buy this book.

11. If you want one book to give to everybody at Christmas, buy as many copies of this book as you require.

You’ll probably have gathered by now that I quite liked it. So warm, so human, so witty, so wise, I wish I’d written it myself. In fact, I wouldn’t half mind being Peggy Leon. I want to live in her world.

Any complaints? Too short. I could have done with another 800 pages or so. No matter. Buy the book anyway. And a final conditional . . . if you don’t, more fool you.