The book is based around 14 papers of mine on consciousness from the last 15 years or so. I have reworked the papers in some places to avoid repetition and create more of a narrative flow. It is quite possible to read it from the beginning, although at 600 pages I don't know how many people will read it from beginning to end. The first five and last two chapters are fairly accessible to nonphilosophers, with some technical material in between.
The OUP website has a table of contents. The early chapters concern the problem of consciousness, the science of consciousness, and the metaphysics of consciousness. My own view is that these chapters provide a better entry point to the my nonreductive view of consciousness than do the early chapters of The Conscious Mind (for both philosophers and nonphilosophers); we'll see how widely that view is shared. The later chapters concern concepts of consciousness, the contents of consciousness, and the unity of consciousness.
There is also plenty of new material, e.g. in a substantial new introduction, afterwords to some of the papers (e.g. a substantial afterword on "First-Person Data and First-Person Science"), an unpublished much-longer version of "The Two-Dimensional Argument Against Materialism" (with an afterword on "Other Anti-Materialist Arguments"), and new footnotes marked with asterisks throughout the book, responding to objections in the literature and pushing things forward in other ways.