In 1864, Colonel James Harvey Blood, wounded in the American Civil War, sought treatment from a ‘spiritual physician’ named Victoria Woodhull. In the midst of a trance, Victoria told him that they would get married. Never mind that he was already married, as was she: Blood accepted Victoria’s proposal on the spot, abandoned his wife and daughters and eloped with her to the Ozarks. The couple eventually settled in New York City, where they mixed radical politics with mysticism.

‘Every evening, at eleven o’clock,’ writes John Kaag, ‘James Blood welcomed a faithful audience into his home on Great Jones Street.’ The lights went down; Victoria, a former actress, took centre stage. ‘Apparently possessed by ghostly voices, she held forth on topics that ranged from the destiny of women’s rights to the fluctuating prices of commodities.’ Among those who fell under her spell was the shipping and railroad magnate Cornelius Vanderbilt. One of her tips alone made Vanderbilt $1.3 million. But it wasn’t the phantoms he had to thank. Victoria had developed a sideline in insider trading: she offered spiritual healing to local stockbrokers; they told her their secrets; the ‘spirits’ passed them on to Vanderbilt. In 1870, this talented fraud opened the first women-centred brokerage in history. Harper’s Magazine called it ‘the bewitching brokers’.

American Bloods is good history. The story it tells is exotic yet familiar, hinting at how we got where we are today. Kaag takes us on a tour of the Blood family tree – a lineage of pioneers, industrialists and thinkers – concentrating on the men. The author’s chief interest