While I was reading this book through the first time I praying about if I should continue because the writer of the book is from a different "school of theology" than I (just because its different doesn't make it wrong). As I prayed about it and spoke with my husband I came to the conclusion that it is fine to read this book and to recommend to others who would benefit from it because the material is honoring to Christ and what is close to his heart (marriage). As a Christian, I ultimately need to focus on things that are going to bring me closer to Christ, build His kingdom, and strengthen my marriage.
When I read I keep a journal close by (on my smart phone) so I can take notes to reference the material when I really needed it. I know some people write in the margin or highlight in their books, however I tend to lend my books out to others so the journal works best for me. My suggestion is to take notes, anyway that works best for you.