This chapter discusses intellectual changes caused by the atrophy of the white matter of the frontal lobes which brought about a severe and stable dysfunction of the frontal cortex. It analyzes disorders in problem solving, using as an illustration a case when the growth of a tumor in the medial sections of the frontal area resulted in the gradually evolving atrophic process in the white matter of the frontal lobes which we could observe for a sufficient period of time. The chapter also discusses the case if Patient B, 47-years-old, a colonel in the air force, was admitted three times to the Institute of Neurosurgery. The provided data reveals a drastic difference between the intellectual disorders of patient B suffering from massive atrophy of the frontal lobes, and the intellectual defects caused by an injury both to the basal sections of the frontal lobe and the posterior-frontal sections of the left hemisphere.