Its easy to read, explains the thyroid function, symptoms of disease & side effects of treatment. I've read it cover to cover & refer to it on occaison.
Another suggestion: The Complete Thyroid Book by Kenneth Ain & M. Sara Rosenthal
This is a bigger book & I would never dare to read it cover to cover but its a good reference book for specific topics like diets & to understand your test results.
These books are from more of a traditional modern medicine viewpoint, less about the homeopathic stuff that I find all over the internet.