From what I read on the website it kind of sounds like AP for Atheists. It also looks like it was first written in the 1970s… and sounds like bunk to me from what I can see.
It is heavy on evolution and seems to be secular humanist in philosophy. The parts that are close to AP seem ok-- it’s more the overall philosophy of this person that is troublesome.
Quotes from the website that I think are questionable as they seem to deny our spiritual soul and objective morality:
According to Jean Liedloff, the continuum concept is the idea that in order to achieve optimal physical, mental and emotional development, human beings — especially babies — require the kind of experience to which our species adapted during the long process of our evolution.
…[Determining what is good for us] has for many millions of years been managed by the infinitely more refined and knowledgeable areas of the mind called instinct.
What is meant here by “correct” is that which is appropriate to the ancient continuum of our species inasmuch as it is suited to the tendencies and expectations with which we have evolved.
There is no essential difference between purely instinctive behavior, with its expectations and tendencies, and our equally instinctive expectation of a suitable culture, one in which we can develop our tendencies and fulfill our expectations, first, of precise treatment in infancy, and gradually of a (more flexible) kind of treatment and circumstance, and a range of requirements to which adaptation is ready, eager, and able to be made.