The essential features of the major benign and malignant vascular tumors affecting infants, children and adults have been presented. Major emphasis has been placed upon the classification and treatment of hemangiomas, although malignant vascular tumors are discussed, and extensive and selected references are cited. The classification system of hemangiomas presented in this monograph is based upon the clinical prognosis of the angioma. The principles of treatment for hemangiomas based upon our clinical classification are discussed and may be summarized as follows: 1. The diagnostic features and prognosis vary with the variety of the angioma. 2. Spontaneous regression occurs only with juvenile hemangiomas, and the major involution occurs before age 5. 3. Patients with rapidly growing capillary cavernous hemangiomas should be treated with steroids. 4. Treatment modalities that increase scarring of the surface epithelium are contraindicated. 5. Intradermal and cirsoid angiomas do not spontaneously regress. 6. Congenital A-V fistulas require aggressive surgery. 7. The ultimate deformity resulting from angiomas may be greatly reduced by plastic surgical techniques. 8. Radiation therapy is never indicated for the treatment of hemangiomas. 9. The psychologic impact of the congenital deformity on patients is generally more detrimental than comparable postsurgical or traumatic deformities.