The basic premise of the book is that the author goes through a personal crisis - her failed marriage - and finds enlightenment in hedonism and platitudes, and the main the tool which she uses for this year-long quest, is not, as one would think an airplane, but magical thinking.
The following quote sums up what's worst about it goes as follows:
I couldn't care less about evidence and proof and assurances. I just want God. I want God inside me. I want God to play in my bloodstream the way sunlight amuses itself on water.
After this I could not take the book, or it's author seriously.
If you don't mind magical thinking, naivete and wishful thinking as long as it gets a happy ending then you can read it, but be prepared for a lot of platitudes, and thinking along the lines of the above quote.
The writing itself is not bad. You can tell this isn't the first thing Gilbert wrote, and that she isn't doing it as a side job or as a hobby but as a full time profession.
Still a little professionalism doesn't make up for the fact that the ideas and the way of thinking presented in it are terrible and childish.