Dot remembers a library visitor asking for a book with a blue cover. There might have been a boat. Or a dog. Dot asked what happened in it, and the visitor described a story she had never heard. Together they found a different book, with a green cover and no boat at all. He returned a week later to say it was excellent. Beside her hospital bed, Dot has a paperback whose cover is mostly hidden by a knitting pattern. Classification, she says, has its limits.