In this review, I summarized the biology of gliomas. Through past clinical and basic studies, I reviewed the evidence of the cell of origin of gliomas and the presence of brain tumor-initiating cells in gliomas, which are driven by multiple genomic alterations. In addition, the complicated tumor heterogeneity and neuronal-glioma network were studied. These mechanisms may underlie the treatment resistance and poor prognosis and support the identification of novel therapeutic targets for gliomas.