Cognitive dysfunction is an important domains in Neuropsychiatry. Association between cognitive impairment and schizophrenia was established since the term Dementia Praecox which first introduced by Arnold Pick (1851-1924)and popularized by Emil Kraepelin (1856-1926). Recently many researches concerned with the domain of cognitive impairment in schizophrenia regarding assessment, and early interference. This book is a small step towards more recognition of aspects of cognitive impairment in late onset schizophrenia in comparison to early onset one.