A great book! Demonstrates and explains the discrepancies introduced by Abhidharma, compared to the Early Texts. If this stuff interests you, proceed to Hua-Yen Buddhism (e.g., "Entry to the Inconceivable"), although she does not mention Hua-Yen. I am now ordering books from her bibliography.
Joanna Macy cuts through the nonsense dispensed in thing like the the "Tao of Physics" to reveal the real scientific basis of Buddhist concepts. Drawing heavily on Systems theory (cybernetics), she shows that the Buddhist view of the universe as system of ever-changing subsystems in dynamic interaction is not just a scientifically valid view, but a profoundly spiritual one as well. She lights the way to a Buddhism that is no longer dependent on supernaturalism, but yields nothing of its profundity. Her interpretations of traditional Buddhist concepts like no-self and karma are masterful. Every Buddhist should read this book.