This book provides a clear and comprehensive guide to the clinical prescription of lithium that draws upon evidence-based knowledge of its mechanisms of action. The book is divided into two parts, on the science of lithium and the practice of lithium therapy. The former covers aspects such as the properties of the lithium ion, pharmacokinetics and pharmacodynamics, impact on neurotransmission, and gene expression modulation. The section on practice includes discussion of variability in response to lithium, use of lithium in the treatment of bipolar disorders, its value in suicide prevention, administration during pregnancy and in the pediatric age group, and side effects. Lithium is arguably the only true mood stabilizer, and its multifaceted effects across many clinical domains have given rise to a resurgence of interest in recent years, fuelled by both researchers and clinicians. Nevertheless, its use remains constrained by exaggerated concerns about potential side-effects.