“Then somebody said to me: Your son looks very like his uncle. It is almost as if he is his own son. And that made me think for the first time: Is my brother the father of my son? I looked at the two of them when they were sitting together and I thought that too. They are very alike.

“I am very fond of my brother. He is my twin, and we have done everything together all our lives. But I do not like the thought that he is the father of my son. I would like to talk to him about this, but I do not want to say anything that may cause trouble in the family. You are a wise lady, Aunty: What do you think I should do?”

Mma Ramotswe finished reading the letter and thought: surely a twin should know how funny this sounds—after all, they are twins. If Aunty Emang had laughed on reading this letter, then it was not apparent in her answer.

“I am very sorry that you are worrying about this,” she wrote. “Look at yourself in the mirror. Do you look like your brother?” And once again that was all she had to say on the subject.

Mma Ramotswe reflected on what she had read. It seemed to her that she and Aunty Emang had at least something in common. Both of them dealt with the problems of others and both were expected by those others to provide some solution to their difficulties. But there the similarity ended. Aunty Emang had the easier role: she merely had to give a pithy response to the facts presented to her. In Mma Ramotswe’s case, important facts were often unknown and required to be coaxed out of obscurity. And once she had done that, then she had to do rather more than make a clever or dismissive suggestion. She had to see matters through to their conclusion, and these conclusions were not always as simple as somebody like Aunty Emang might imagine.

It would be tempting, she thought, to write to Aunty Emang when next she had a particularly intractable problem to deal with. She would write and ask her what she would do in the circumstances. Here, Aunty Emang, just you solve this one! Yes, it would be interesting to do that, she thought, but completely unprofessional. If you were a private detective, as Mma Ramotswe was, you could not reveal your client’s problem to the world; indeed, Clovis Andersen had something to say on this subject. “Keep your mouth shut,” he had written in The Principles of Private Detection. “Keep your mouth shut at all times, but at the same time encourage others to do precisely the opposite.”

Mma Ramotswe had remembered this advice, and had to agree that even if it sounded like hypocrisy (if it was indeed hypocrisy to do one thing and encourage others to do the opposite), it was at the heart of good detection to get other people to talk. People loved to talk, especially in Botswana, and if you only gave them the chance they would tell you everything that you needed to know. Mma Ramotswe had found this to be true in so many of her cases. If you want the answer to something, then ask somebody. It always worked.