This issue of Psychiatric Clinics devoted to young onset dementia or early onset dementia presents information that is salient and valuable for clinical practice. The issue will update knowledge, present cultural and practical perspectives, examine priorities, and show opportunities for psychiatry practice and research in this group of dementias. Topics include: An epidemiologic perspective on young-onset dementias; The frontotemporal dementias; Posterior Cortical Atrophy: an atypical variant of Alzheimer disease; Rapidly progressive young-onset dementias: neuropsychiatric aspects; A guidance for the neuropsychiatric examination of young-onset dementias; Neuropsychological assessment and differential diagnosis in young-onset dementias; Brain imaging in the differential diagnosis of young-onset dementias; Role of genetic counseling in the diagnosis and management of young-onset dementias; Brain histopathological examination in neuropsychiatry practice and research; Pharmacologic interventions for young-onset dementias; Psychosocial and rehabilitative interventions for young-onset dementias; Public advocacy and community engagement for young-onset dementias; and Integrating dementia care and primary care. Dr Chiadi Onyike, expert in the field of young onset dementia leads a team of expert authors who feature the potential for overlooked or missed diagnoses; neuropsychiatric phenomena taking on greater importance; and the crucial neurologic examination to rule out other disease, to have a thorough knowledge of differential diagnoses, and to be vigilant with the emergence of neuropsychiatric phenomena that can indicate young onset dementia.