This is an excellent book for understanding the complexity of thyroid hormone action and how it is related to other hormones,vitamins, minerals,enzymes, gene transcription and protein expression , so to all the functions in our body. Because when something goes wrong, i.e.you as a thyroid patient are not responding well to classical T4/Levothyroxine therapy you will have to learn all about the parts of this great picture in order to understand and improve your condition. Paul Robinson helps us through all his books to understand the sience behind what s going on in our body during hypothyroidism, how to connect this to symptoms &signs and to the results of our tests ,so that we can figure out what our body is saying to us, what our hormonal status is and if our treatment is efficient or not. As a thyroid patient and as a doctor also, I highly reccomand Paul Robinsons books to all thyroid patients with related hormonal issues as a guide on the journey of their ilness to hormonal ballance and health and to all doctors , my collegues, wich treat patients with thyroid disorders for a better understanding and a better correlation of the test results with the symptoms &signs of the patients which is so much important in order to prescribe the appropriate thyroid therapy for an individual patient, instead of only relying on blood tests ,and sadly I have to say that this is the way how thyroid patients are mostly treated today. Hoping for a more individualized approach of the thyroid patient and that all the forms of thyroid hormone therapy are available everywhere when needed!