ABC of Multimorbidity is the first title to provide primary care practitioners with a practical approach to the complex issues of treating and managing patients with more than one morbidity. Ageing populations and earlier diagnosis of chronic conditions mean more people are living longer with multimorbidity. However, treatment guidelines are often designed for treatment in isolation of other morbidities. Multimorbidity management therefore requires a more patient centred approach and greater knowledge and coordination of existing services. Effective multimorbidity management both improves overall patient well-being and reduces the overall demand on health services. ABC of Multimorbidity examines how multimorbidities can be addressed within primary care, from the GP and family physician consultation through to the effective use of a range of health care services. It addresses complex issues such as polypharmacy, mental health, patient safety, patient involvement in self-management, and the role of the practitioner. It then provides guidance on how multimorbidities can be best treated and managed within primary care through specific interventions to improve outcomes. From an international, primary care editor and contributor team, ABC of Multimorbidity is a practical resource for general practitioners, family physicians, practice and specialist nurses, and others caring for multimorbid patients. It is also relevant for junior doctors, medical trainees and students.