I would highly recommend this book to anyone suffering from persistent spots or acne. No matter what the doctors or dermatologists tell you - what you eat has a direct effect on your skin. The only reason they won't admit to this is because they need to promote pills/creams from pharmaceutical companies (in which acne is a huge source of revenue and BIG business). I started to suffer from spots later in my life and wondered what could have caused it. I then drastically changed my diet - no more refined foods (white bread, white pasta, white rice), no more take-aways, no more processed foods (ready-made meals), no more cane sugar (replaced by honey). I also cut out dairy as I suspected it was causing me problems. This seemed to get rid of about 90% of my spots which I was very happy with. Elaine also suggested to check for Lactose in pills/medication you might be taking. I then discovered that a certain medication I was taking did contain Lactose! Since I couldn't change my medication, I thought I would give Lactase enzymes a try. I started taking a Lactase enzyme with my medication and to my surprise, the last 10% of spots completely cleared up. I am now 100% clear!
On another note, you must be patient with this. It takes some experimentation. You might be lucky and clear up as soon as you change your diet to a more healthful one. For others, it might take a little longer due to other factors such as food intolerances. Everyone is different - just because you know someone who can eat whatever they like and has clear skin doesn't mean everyone can. We all have different digestive systems which react in different ways to certain foods. As Elaine suggests, cut out all foods that are known acne offenders, then you can reintroduce them one by one to pinpoint YOUR offender. A food intolerance test might also help as you could be eating foods that your body simply can't digest properly which then manifests itself as spots on your skin.
There is also a section on maintaining a good skin care routine. For instance, a certain face cream you are using could be blocking your pores and causing you spots (I also found this with a cream I was using so changed it).
All in all, there is great advice all throughout the book.