Bipolar Depression Bipolar depressions are often intractable and potentially deadly. We find from Kraepelin's lectures that thyroid hormones have been in continuous use in psychiatry for at least 120 years, the oldest continuous treatment in psychiatry with the exception of psychotherapy. The use of high doses of thyroid hormone is recommended for bipolar depression in at least two major treatment guidelines: the Texas Medication Algorithm Project for bipolar I depression and the Canadian/ISBD guidelines for bipolar II (2013). There are numerous studies showing its effectiveness including a randomized double-blind placebo-controlled study. Neuroimaging studies show that high doses of thyroid decrease overactive areas in the brain that are associated with depression. In other words, it helps restore normal neurophysiologic functioning, possibly, by correcting low cellular thyroid levels, caused by dysfunctioning mitochondria and low ATP levels. High dose thyroid is well tolerated and is as safe as or safer than most other treatments used for bipolar disorders. High dose thyroid is far safer and far more effective than antidepressants. In fact, theories predict that high dose thyroid may decrease the medical sequela associated with the bipolar disorders allowing our patients to live healthier and longer. Despite all these factors high dose thyroid is rarely used or even talked about for bipolar depression. Here is a book that packages both the "how to" of the practical day-to-day use of high dose thyroid and the evidence base of its efficacy and safety for treating bipolar. The book debunks the myths surrounding high dose thyroid offering definitive proof that it differs from hyperthyroidism. Given the high rate of morbidity and mortality of bipolar depressions. Given the uncalculable suffering by patients and their families. Given the safety and tolerability of high dose thyroid. Given the tremendous cost to society. Given the dearth of effective treatments the question is no longer why use thyroid hormones for treatment. The question asks itself: Why are we not using thyroid hormones to treat bipolar disorder?