Part of the new series Advancing the Research Agenda for DSM-V, Diagnostic Issues in Dementia comprises nine chapters with research suggestions for consideration for the upcoming DSM-V process, reflecting the nascent effort toward a new diagnostic nomenclature in the still rapidly evolving field of dementia. Here, 18 experts provide critical pieces of the dementia diagnostic story: Alzheimer's disease and the aging brain, the challenges of changing our general definition of dementia, diagnostic nomenclature, the growing evidence for mild cognitive impairment as an identifiable entity suitable for inclusion in DSM-V, neuropsychological testing, behavioral syndromes and the need to better focus appropriate therapy, biomarkers in dementia for inclusion in diagnostic criteria, specific imaging modalities, and the sobering assertion that, despite the tremendous explosion of information in this field, genetic profiles except for rare Mendelian disorders are not yet ready to make substantial contributions to nosology. Within the vast and rapidly expanding literature of dementia, this remarkably concise and insightful collection reviews today's and suggests directions for tomorrow's important diagnostic and research issues in dementia, and as such is a "must read" for clinicians and researchers alike.