Hyperhidrosis is defined as excessive sweat production beyond requirements for temperature regulation. It can be idiopathic, secondary to other systemic conditions such as endocrine or autonomic dysfunction, as well as a side effect to medication. An estimated 7.8 million Americans suffer from hyperhidrosis with up to 1.3 million reporting severe disease. Affected patients can experience limitations in occupational and social circumstances. As a result, patients with hyperhidrosis often experience decreased physical and emotional wellbeing, difficulty in personal relationships, and can suffer from social stigmatization. This book discusses several different causes of hyperhidrosis, as well as treatment options and outcomes.