Acute lymphoblastic leukemia (ALL) is the most common malignancy diagnosed in children, representing nearly one third of all pediatric cancers. The annual incidence of ALL is about 30 cases per million people, with a peak incidence in children aged 2-5 years. Although a few cases are associated with inherited genetic syndromes, the cause of ALL remains largely unknown. This issue presents articles that discuss current thinking on the diagnosis and treatment of the disease. Articles specifically emphasize molecular genetics, allogeneic stem cell transplantation, and treatments including, clofarabine, nelarabine, rituximab, and PegAsp.