As Good as God, as Clever as the Devil: The Impossible Life of Mary Benson, By Rodney Bolt

Edward Benson, the future Archbishop of Canterbury, was 23 when he proposed to his cousin Mary "Minnie" Sidgewick. She was 12. They married when she was 18.

Edward was passionate, unbending and domineering. Mary was frightened and, in her own words, "childish in understanding", but determined to mould herself to him, to be "a true woman".

Over time, Mary mastered the dark arts of household management and – even tougher, given her fizzing intelligence, desires and energies – self-management. She raised six clever, idiosyncratic children. But she could never return Edward's passion and her intense emotional and sensual involvements were with women. She recorded in a retrospective, self-critical diary how "the suppleness, litheness of the limbs stirred me to uneasy restlessness, a fierceness, a tingling" and how she fought to resist this yearning.

Much of the joy of this effervescent biography is in its detail. The names which Mary and Edward's children gave their guinea pigs (Atahualpa, Ixlitchochitl, Edith Mitchinson); how Edward told Henry James the "meagre elements of a small and gruesome spectral story" that became The Turn of the Screw.

In his preamble, Rodney Bolt explains that writing this book presented "an acute version of a well-worn ... problem, that of the tricky relation between an author's life and work". Mary didn't write for publication, but four of her children did and their work could be teasingly autobiographical. Sons Arthur, Hugh and Fred (E F Benson, author of the Mapp and Lucia novels) were so prolific that their sister Maggie half-joked that unless they emigrated, English literature would be "flooded". They didn't. In 1906, Punch ran a cartoon captioned "Self-denial week: Mr A C Benson refrains from publishing a book". He didn't.

Bolt peppers Mary's biography with extracts from the Bensons' works and other contemporary writings, which frees him to situate Mary and her family in their socio-historical contexts without having to expound on the position of straight women, gay men and lesbians in Victorian and Edwardian England. And it leaves plenty of space for his readers to exercise their intelligence. Just occasionally, though, I'd have welcomed a more direct and opinionated approach. Was, for instance, Edward's premature wooing of Mary a straightforward example of the Rousseau-ist grow-your-own tradition of wife-sourcing? Or was it every bit as paedophiliac as the way that Arthur, a middle-aged schoolmaster, would gaze enraptured through his young charges' bedroom windows while they undressed?

But that's a niggle and a prurient one. At the heart of this book is an extraordinary woman who "evoked rather than dazzled", whose strengths – an ability to listen, an acute perceptiveness and precise tact – were founded on openness, understanding and profound self-awareness. A woman who came to believe that "Love is God", rather than vice versa. And who deserves to be written and read about.