Unfortunately, the surviving Doors members, and other people closer to Morrison have pretty much unanimously denounced this book.
This version of Jim is basically one dimensional, and definitely sensationalized to match his public persona.
It is likely that much of the public idea of him actually comes from this book, as it has had a lot to do with his modern mythos.
Though I haven't read any other Morrison biographies at the time of this review, while I was reading this one I did feel like I wasn't reading about a real person. Real people have a variety of characteristics, goals, etc. It does mention his poetic side and such, but it very much gets swept away in his overall animalistic portrayal, while going quite quickly through his life.
The book definitely feels like it was written to sell, rather than to be an honest nuanced look at an interesting person.