The Philosophy of Organism: Can anyone provide insight into the basics of the philosophy, especially as it relates to Whitehead's Process and Reality?

In a recent thread a responder recommended a book titled A Key to Whitehead’s Process and Reality. Now mind you, the book is a key to Whitehead’s Process and Reality and is supposed to make Whitehead’s book accessible to beginners. Man am I humbled.

In the opening paragraphs of the key, reference is made to The Philosophy of Organism which I gather Whitehead developed. The veracity of the only article on wiki regarding the Philosophy of Organism is under dispute so no help there as to the basics regarding the philosophy.

i am hoping that some of you fluthrites can provide basic information about the philosophy as it seems a basic understanding of the philosophy is key to understanding the key.

This not a question about the rightness of wrongness of Process and Reality or Philosophy of Organism. It’s a question about what, you know?