Jean Liedloff, who has died aged 84, was the author of The Continuum Concept: In Search of Happiness Lost (1975), in which she outlined her belief that babies should be continuously carried by, and never separated from, their mothers, until such time as they are able to crawl away by themselves. She advocated co-sleeping and on-demand breastfeeding and believed that children should be central to their parents’ world, but not the centre of it. Many credit her with being the mother of attachment parenting.

Liedloff was born in New York and grew up in Manhattan. As a child, she was attracted to Tarzan and jungles. “It seemed to me,” she said, “that there was something primal, something right about [the jungle]. Tarzan represented a pure being.” She attended Drew Seminary for Young Women, in Carmel, New York, and then went on to Cornell University, but never graduated. She modelled for a while, and wrote.

On her first trip abroad, to France, and then Italy, she was introduced to a “blond, blue-eyed count called Eurico”, a man whom Liedloff recalled was “so successful with women, he had become extremely conceited and I would have nothing to do with him”. However, when he announced he was going to the South American jungle to search for diamonds and asked her to go with him, with just 20 minutes’ warning before the train left, she went, “jumping on the train as it was pulling out of the station”.

Liedloff spent five months in the jungle. She was to return four more times and at one point contemplated living there. She observed, most famously, the Yequana tribe of Venezuela. Babies were in continuous physical contact with their mothers until they could crawl, then children of all ages, from babies just out of arms to teenagers, played all day, unsupervised, but were responded to – without judgment – the moment they needed anything. “Not only did the children not fight, they never even argued,” she said.

Tall, blonde, beautiful and dressed in a leopardskin-patterned bikini, she cut an incongruous figure in the jungle. She seemed completely devoid of all vanity and rarely talked about herself.

After her fifth trip to Venezuela, she decided to write The Continuum Concept, which was published in 1975 and later translated into more than two dozen languages. The more she learned about the Yequana people, the more she grew disdainful of childcare experts in the west: “In the jungle, every man, every woman, every child knows how to take care of babies … Very small children are trusted to take care of infants because, five minutes ago, they were babies themselves … Here we are, great big grownups reading books about how to take care of babies. I’d be embarrassed to admit to the Indians that our women don’t know how to take care of their children until they read instructions written in a book by a man they’ve never met.”

Liedloff was a founding member of the Ecologist magazine. For a while she lived in London, where she lectured on The Continuum Concept. She never married, nor had children. She eventually moved to Sausalito in San Francisco, where she lived on a houseboat with her cat, Tulip, until her death.

I was due to interview her in 2008. Her publicity people asked me to fly out to California. It would be madness, I explained, to fly out to meet the author of The Continuum Concept, with all she stood for, and leave my own young, breastfed daughter behind for days. Liedloff, then in her 80s, agreed, and offered to fly to London to meet me. In the event, she did not make it, as the result of a knee injury.

As modern methods of parenting grew further away from the continuum concept, Liedloff became ever keener to spread the word about what she had discovered. She longed to be on Oprah. “We oppose the baby from the start, coached by experts and the society around us, not by our own feelings. We wage a war of wills: the baby is hungry and cries and we say no, it’s got to be four hours between feedings.”

Liedloff felt that we had lost our trust in our children and ultimately ourselves. Parents had forgotten how powerful they are to young children and how easy it is to make them feel as if there is something wrong with them, even with a look. “My mother was the master of ‘the look’. If my sister and I were talking at night when we were supposed to be asleep, she would open the door and peer in at us with this hurt, disappointed expression, and then close it again. I would rather she’d beaten me with a bullwhip.”

• Jean Liedloff, writer, born 26 November 1926; died 15 March 2011