Glioblastoma (GBM) is a highly malignant brain cancer characterized by uncontrolled cellular proliferation, diffuse infiltration, a tendency for necrosis, significant angiogenesis intense resistance to apoptosis, and widespread genomic aberrations. Glioblastoma multiforme results from a cascade of genetic alterations that begin in a target brain cell and, through unregulated cell division and a panoply of other molecular abnormalities, lead to an expanding mass lesion Among the therapeutic triad of surgery, radiation therapy, andchemotherapy only radiation therapy has been shown to improve survival. Despite aggressive treatments, malignant GBM hasremained difficult to treat, and its overall response to treatment hasremained poor, as has outcome in patients harbouring this lesion. Greater understanding of the tumour biology of GBM has been achieved in the past decade, leading to the prospect of novel targeted therapies and biomarker-based individualization of therapy. The aim of this review is to analyse the tumour biology and the pathologic features of GBM which includes guidelines for classification and diagnosis, the current status of prognostic and predictive biomarkers, and the role of the blood-brain barrier in delivering therapy for GBM.