The author discloses a personal history of undiagnosed mile traumatic brain injury (MBTI) and identifies a typical course of progression of this condition.  He advocates a careful inquiry for possibly head injury whenever the clinical history shows an original period of normal functioning, a progression of disturbance over time, multiple diagnoses, and poor response to treatment with medication. He discusses the use of quantitative electroencephalography (QEEG) in assessing possible mild traumatic brain injury, describes typical features of quantitative electroencephalography in mild traumatic brain injury, and cautions ab out the frequency false negatives.  He provides two case histories showing the progression of disturbing cognitive, personality, and impulse control problems following early head injuries.