This chapter discusses the most relevant and recent advances in clinical diagnosis, imaging, pathology, genetics, and treatment strategies in frontotemporal lobar degeneration (FTLD). Special emphasis is on the genetically determined forms of FTLD. FTLD refers to a group of neurodegenerative diseases comprising the clinical and pathological entities frontotemporal dementia (FTD), progressive nonfluent aphasia (PNFA), and semantic dementia (SD). Although the diagnostic criteria for FLTD are mainly clinical, a relationship between the symptoms and the predominantly affected areas exists with FTD mainly affecting the frontal lobes, PNFA affecting the left frontal lobe, and SD affecting the left temporal lobe. The frontotemporal dementia associated with motor neuron disease (FTD-MND) is also discussed. Early symptoms in FTD patients are dominated by impairment in social behavior and character changes. Additional symptoms include a wide range of frontal-type behaviors, mostly of the disinhibited form, along with speech alterations without true aphasia. Dietary changes, including binge eating, are common among FTD patients. The familial forms of FTLD discussed are FTDP-17 tau-positive families and FTDP-17 tau-negative, ubiquitin-positive families.