This book summarizes the broad and rapidly evolving field of geriatric pharmacotherapy, which is becoming increasingly relevant for practicing physicians who care and prescribe medications for older patients. Around the globe, ageing populations are associated with an increased prevalence of chronic diseases. Older adults are often affected by multimorbidity, i.e., suffer from more than one chronic disease. The main consequence of multimorbidity is polypharmacy, which is commonly defined as the regular use of five or more medicines. Polypharmacy has now reached epidemic proportions in our societies, and is associated with an increased risk of drug-drug interactions, drug-disease interactions and adverse drug reactions. The management of polypharmacy in older patients with complex multimorbidity poses several challenges and needs to be based on specific knowledge and prescribing expertise. The aim of this book is to provide a comprehensive update on thefield, and to share the expertise needed to optimize the management of pharmacotherapy in older patients.