IT IS TO the credit of this serious and scholarly book that it fails to live down to its title. 'Mad Madge' was coined by nineteenth-century critics, Katie Whitaker tells us, and was unjust. It is a shame, then, that she uses it herself, and I can only think her publishers persuaded her.

Then, in her prologue, she tells us something else she will not live down to (or perhaps 'up to' this time). She sets out four questions about Margaret, Duchess of Newcastle. How had she come to break with social convention and write all her books? What sort of person had