“I Shall Wear Midnight” does all the things that Terry Pratchett does well: it provides insights into human weakness, leavens them with hope and courage and spices them with a generous dash of humour.

What makes this an exceptional book, even for Terry Pratchett is the development of the young witch of the Chalk, Tiffany Aching. I confess to having fallen a little in love with Tiffany Aching in the previous books. She is brave, selfless and determined to do the task in front of her even when the task is immeasurably bigger than she is.

This is the book where Tiffany grows up. There is almost a sense that Pratchett is saying goodbye to her and launching her into her adult life. In this book, Tiffany comes to understand that doing the right thing is a choice that may set her so far apart that she may have no route to a normal happy life. She also starts to see the danger that what starts as setting yourself apart can become setting yourself above.

Although other witches appear in this book and the Wee Free Men are still at her side at all times, especially when she’s ordered them not to be, the evil threat in this book is one that Tiffany must face alone. It is, essentially a test of her own ability to choose to not to give in and become something monstrous.

The threat comes from an entity created and sustained by hate. It spreads hate like a contagion, changing normal individuals into a vengeful mob. Pratchett highlights our ability to hate and fear categories of people in the abstract even when we do not apply the hate to individuals in that category that we know. It counter-poses female “headology” – getting on with all the mundane or unpleasant things that make life work, with male “theology” that provides a model of who to hate and who to punish.

In the end, it tells us that fear and anger blind us, allowing hate to bind us. Our protection is not just “First Sight and Second Thoughts” but the ability to reach out to others and build trust and affection that hate cannot break.

The title of the book “I shall wear midnight” highlights another strong theme in the book: doing things in their right season. Tiffany Aching pushed herself to be a witch of the Chalk when she was still a child. Her childhood was the price she paid for that. Yet Tiffany declines to wear black, Tiffany wants to join in the dance of life, Tiffany is willing to die to protect what needs to be protected but she’d rather live and love and grow. During this book, Tiffany understands that not only that she can be a witch and still be a woman but that being a woman will make her a better witch. She will grow old and die. But not yet. She shall wear midnight when she is old but today she is young and she is taking her time in the sun.

It is the ability to weave these messages into a book that is funny and exciting and easy to read that sets Terry Pratchett apart as a unique voice.