The hair test book (Hair Test Interpretation by Dr. Andrew Cutler) stands on it's own. You really don't need a working knowledge of mercury toxicity to understand how to read hair tests to determine if you're mercury toxic, so, it's not really necessary to buy the other book (Amalgam Illness by Dr. Andrew Cutler) first.

I would also add that the reason this book is necessary is because it really is a bit complex to determine if you have mercury toxicity. Few people know that mercury normally shows up low even in mercury toxic persons until they are extremely sick. Thus the reason for the book. It allows you to find other signatures that are indicators of mercury toxicity, such as high calcium (because of impaired magnesium utilization). This is the stuff the typical doctor is clueless about.

Anyway, the hair test book is great, but a bit complex, but well worth it.

Hope this helps.