“That is a very special engine,” said Mr J.L.B. Matekoni, looking at her anxiously. “There is no other engine like it in Botswana. One day I shall finish fixing it.”

They moved on. The next room was a bathroom, which was clean enough, thought Mma Ramotswe, even if rather stark and neglected. On the edge of the bath, balanced on an old white face-cloth, was a large bar of carbolic soap. Apart from that, there was nothing.

“Carbolic soap is very healthy soap,” said Mr J.L.B. Matekoni. “I have always used it.”

Mma Ramotswe nodded. She favoured palm-oil soap, which was good for the complexion, but she understood that men liked something more bracing. It was a bleak bathroom, she thought, but at least it was clean.

Of the remaining rooms, only one was habitable, the dining room, which had a table in the middle and a solitary chair. Its floor, however, was dirty, with piles of dust under the furniture and in each corner. Whoever was meant to be cleaning this room had clearly not swept it for months. What did she do, this maid? Did she stand at the gate and talk to her friends, as they tended to do if not watched closely? It was clear to Mma Ramotswe that the maid was taking gross advantage of Mr J.L.B. Matekoni and relying on his good nature to keep her job.

The other rooms, although they contained beds, were cluttered with boxes stuffed with spark plugs, windscreen-wiper blades, and other curious mechanical pieces. And as for the kitchen, this, although clean, was again virtually bare, containing only two pots, several white enamelled plates, and a small cutlery tray.

“This maid is meant to cook for me,” said Mr J.L.B. Matekoni. “She makes a meal each day, but it is always the same. All that I have to eat is maizemeal and stew. Sometimes she cooks me pumpkin, but not very often. And yet she always seems to need lots of money for kitchen supplies.”

“She is a very lazy woman,” said Mma Ramotswe. “She should be ashamed of herself. If all women in Botswana were like that, our men would have died out a long time ago.”

Mr J.L.B. Matekoni smiled. His maid had held him in thrall for years, and he had never had the courage to stand up to her. But now perhaps she had met her match in Mma Ramotswe, and she would soon be looking for somebody else to neglect.

“Where is this woman?” asked Mma Ramotswe. “I would like to talk to her.”

Mr J.L.B. Matekoni looked at his watch. “She should be here soon,” he said. “She comes here every afternoon at about this time.”

THEY WERE sitting in the living room when the maid arrived, announcing her presence with the slamming of the kitchen door.

“That is her,” said Mr J.L.B. Matekoni. “She always slams doors. She has never closed a door quietly in all the years she has worked here. It’s always slam, slam.”