Arteriovenous malformations (AVM) represent some of the most complex and challenging pathologies for the modern physician to properly diagnose and manage. In this comprehensive guide, we detail the natural history, diagnosis and management of AVMs. The first eight chapters are dedicated to brain AVMs. Chapter 1 describes the natural history of brain AVMs, the understanding of which is crucial to deciphering the relative risks and benefits of AVM treatment. Chapter 2 focuses on the surgical treatment of brain AVMs. Chapters 3 and 4 delineate the role of endovascular embolization in the management of brain AVMs. Chapter 5 analyzes the outcomes of stereotactic radiosurgery for Spetzler-Martin grade III AVMs, which are the most heterogeneous subgroup of AVMs. Chapter 6 describes the role of stereotactic radiosurgery for large brain AVMs, which are notoriously difficult to safely and effectively treat by any means. Chapter 7 focuses on heavily charged particle beam radiosurgery for brain AVMs. Chapter 8 puts it all together by analyzing the relationships and interactions among the different treatment modalities for brain AVMs; when utilized synergistically, the morbidity of each therapy is minimized while its maximum benefit is extracted. The last two chapters are dedicated to Osler-Weber-Rendu syndrome, also known as hereditary hemorrhagic telangiectasia (HHT). Chapter 9 describes the genetics, pathogenesis, and management of HHT, with a focus on the diagnosis of pulmonary AVMs. Chapter 10 evaluates the role of endovascular intervention in the treatment of pulmonary AVMs.