This is a multi-center, open-label, non-randomized Phase I study in patients with brain metastases. Patients will be administered oral Vorinostat and radiation therapy and will be treated for 3 weeks. Patients will be enrolled in cohorts and will be treated at sequentially rising dose levels of Vorinostat combined with radiation therapy. We will initially enter 3 subjects at each dose. If none of the three experiences a dose-limiting toxicity we will proceed to the next dose. If one of the three experiences that level of toxicity, we will accrue 3 more subjects at that dose. If at any time there are two or more dose-limiting toxicities (in the 3-6 subjects) on a given dose, we will drop down to a lower dose. Dose escalation will continue until the MTD of Vorinostat and radiation therapy is established. The MTD will then be one dose below the DLT occurring in at least 1 out of 3 subjects (2 out of 6 patients).