The Times Magazine has an article on Jung's Red Book---a diary of a psychotic break he experience midlife---soon to be published---pictures and all---by Norton. I am not a Jungian, and yet it is impossible to ignore his influence on the field... http://www.nytimes.com/2009/09/20/magazine/20jung-t.html?pagewanted=1&em
When one thinks about the short time we've had psychology with us, but already how tangled the provenance (though I love the bit in the article about analysts' 'pedigree') it gives one pause about the development of other belief systems over the years.
Imagine a new field or belief system is like a tank with people pouring buckets in. Some things might dominate others, but ultimately in the blend it is almost impossible to distinguish original sources. What's left is essentially, not only its own thing, but ultimately a kind of 'mud' (like mixing all the colors in the paintbox) that retains little of its original character and is completely open to the interpretation of those who decant it or add their own buckets.
The collected books of the bible come to mind. As do foundational work in scientific inquiry. (Of which I am not necessarily including psychology, which has always seemed more of a humanistic endeavor than a science with more than a slight scent of cultural hegemony. This is one of the reasons I am very interested in people who work with 'outsiders' and the failure of therapeutic techniques when working with different groups of people.)
However, I think the most intriguing aspect of the article is this idea of before and after. This publication will utterly change the field, especially for members of the cult.