Neurofibromatosis type 1 (NF1), previously known as von Recklinghausen disease, is a neurogenetic disorder distinct from neurofibromatosis type 2 (NF2). Approximately 1:2500 to 1:3500 individuals worldwide are affected, regardless of ethnicity or race. The classic manifestations of NF1 include café-au-lait macules, skinfold freckling, neurofibromas, brain tumors, iris hamartomas, and characteristic bony lesions. In addition, patients with NF1 are at increased risk for learning and intellectual disabilities, aqueductal stenosis, pheochromocytoma, vascular dysplasia, scoliosis, and cancer. In this chapter, we discuss the clinical and molecular features of NF1 as well as how insights into its underlying molecular pathophysiology have revealed new targets for therapeutic drug design.