"Specialists, often tribal chiefs, removed the brains, eyes, and tongues before stuffing the nostrils and skull with flax and burying the head with hot stones so that it gradually steam or cured dry," the book says.
Toi moko were displayed on short poles, usually around the chief's house.
Joseph Banks, the naturalist who accompanied Captain James Cook on his historic first voyage to the South Pacific, was the first European to acquire a Maori head.
He managed to "persuade a reluctant elderly Maori man" to part with it in exchange for a pair of white linen drawers.
But when the old man took the drawers, he then refused to give up the head until Banks "enforced his threats" at musketpoint.
As contact with European whalers and sealers increased, and the desire for guns increased among Maori in the early nineteenth century, the trade is preserved heads took off.
Over the course of the 50 years from Captain Cook's first visit in 1769, trade in human heads "reached such intensity, and inter-tribal warfare escalated so ferociously, that many believed the Maori would be completely annihilated," Dr Larson writes.
The intricate facial tattoos of Maori chiefs were particularly attractive to Europeans.
But they were also the hardest to find and led to slaves being forcibly tattooed and sold to order.
European agents sent over were sometimes killed, tattooed, and sold back to their own unsuspecting countrymen.
Preserved heads were snaffled by private collectors and museums, but also sold in European shops and auction houses as curiosities.
In 1831, the Governor of New South Wales, Ralph Darling banned the increasingly popular practice, saying "there is strong reason to believe that such disgusting traffic tends greatly to increase the sacrifice of human life amongst savages whose disregard of it is notorious".
The 317-page book notes the observation of one nineteenth century collector, Horatio Robley, who said the human head trade had by then stocked the museums of Europe but had also "considerably reduced the population of New Zealand".
Since 2003, more than 70 toi moko have been returned to Te Papa Museum in Wellington from public collections in Sweden, Switzerland, the UK, Denmark, Australia, Argentina, France, Hawaii, the Netherlands, Ireland, Canada, USA, and Germany.
However, it's believed there are at least 100 more in collections around the world.
* 'Severed: A History of Heads Lost and Heads Found', by Frances Larson, is published by Granta.