‘Even now, after working on this book for several years, I find it difficult to explain to strangers where I am writing about,’ Caroline Crampton confesses in The Way to the Sea. It is a hard book to categorise. One might call it a kind of loose-knit, autobiographically inflected portrait of the Thames Estuary, if that helps. Crampton has spent a lot of time on a sailing boat out beyond the eastern reaches of the river with her parents, white South Africans who left the country years ago and took to the sea. Before that, by the time she was six, she had lived in six different houses. But this isn’t a straightforward source-to-sea journey down the Thames, though it is arranged as such, and there aren’t many descriptions of the author’s own experiences on the water.