Despite an ever widening knowledge of the life cycle of tumors of the brain, much remains that is still obscure from both the clinical and the pathologic point of view. This is particularly true of the meningeal fibroblastomas—tumors which, by virtue of their slow growth, often give rise to very few symptoms in the early and even in the later stages of their expansion. Their diagnosis is often difficult. It is because of this, as well as a desire to know more about their clinical expression and histologic structure, that we have reviewed a series of seventy-five cases of meningeal fibroblastomas of the cerebrum which have been observed by us in the clinic and laboratory of the Hospital of the University of Pennsylvania. We have not ventured in this contribution a comprehensive presentation of the subject of cerebral fibroblastoma. We have made no reference to the clinical experience of others,