This book contains four chapters discussing essential facts about lanthanum. Chapter One describes lanthanum complexes with variable coordination and versatile applications. Chapter Two reviews the effects of lanthanum on aquatic organisms. Chapter Three discusses the synthesis and properties of nanodispersed luminescent structures based on lanthanum fluoride and phosphate for optopharmacology and photodynamic therapy of tumor diseases localized in cranial organs and bone tissues. Chapter Four discusses the removal and recovery of lanthanum from aqueous solutions by biosorption.