This is not a book to read for content, it is a picture book to look at if you want to see some pairings that might inspire you for your garden. The content can mostly be boiled down to "Decide how you want to pair up your plants, if it makes you happy, do it, but here are some design terms to use so you can justify your choices."
Lovely photography, but not a great resource for "planting x near y will help the plants flower better," or similar companion gardening wisdom.