OUTLINE: This study will enroll evaluable patients undergoing surgical resection of malignant, grade IV gliomas in both of two groups: those with , newly diagnosed GBM and those with recurrent GBM. Patient, in each group (primary vs recurrent GBM) will be randomized to one of 2 levels of ALA dose (10 and20 mg/kg) to be given orally at 6 hours prior to anticipated midpoint of surgery.