Malignant brain tumors are notorious for high morbidity and mortality. Our deficient understanding of brain tumor pathogenesis is reflected in our inability to cure this disease. Treatment remains palliative at best. The cancer stem cell hypothesis of brain tumors promises to consolidate many observations which have previously eluded neuroscientists and may reveal why aberrations in developmental programs are among the commonest findings in brain tumors. It is ironic that brain ontogeny and cancer - two processes with very different outcomes - exploit similar mechanisms to multiply, migrate,and survive. Implications of this hypothesis extend beyond mere academic interest. It may explain our current failures in the clinic and sets the stage for novel therapeutic paradigms aimed at altering the developmental adaptations of brain malignancies.