I haven't read it, but it sounds very interesting, so I thought I would post a blurb about it here.
Commence blurb( quoted from goodreads.com ):
For many of us who grew up in a theistic world of 'God', the idea of God becoming a Buddha may seem confusing and disorienting, as we tend to think of God as the creator of the physical universe and "the Buddha" as just a human being within this creation. And while it is certainly true that the historical Buddha (Siddhattha Gotama) was a human being just like us, this book examines his past lives as a God, his discourses to the Gods, and central teachings from the Dhamma he taught to shed light on the logic and nature of Buddhist Cosmology and its relationship to the path of spiritual liberation from the things that make us suffer.
One may ask, how could a God who ruled the universe not be fully liberated spiritually, as the awe, overwhelming power, and genius of the physical universe appears beyond human comprehension, and therefore its ruler must have achieved the highest state of being. Complete mastery of the physical laws of the universe - the elusive goal of science - is widely considered the ultimate in human development. But through examining Buddhist Cosmology and the numerous discourses the historical Buddha gave on the nature of the God(s), we learn that the Gods were/are imperfect and addicted to form and/or sense gratification, and had many spiritual fetters that kept them bound to the gross and finer material realms of existence despite significant spiritual advancement.