Sleep Medicine places one of the most essential yet frequently underestimated foundations of neurological health at the center of clinical practice: sleep. Sleep is first and foremost a function of the brain, serving as a critical biological requirement for memory, emotional regulation, immune function, synaptic plasticity, glymphatic clearance, development, and prosocial behavior. Its influence extends across nearly every domain of neurological health and disease.This volume is the first in the 'What Do I Do Now?' series devoted entirely to sleep disorders and their diagnosis and management by neurologists. Sleep disturbances affect almost every neurological condition-not merely as comorbid symptoms, but often as contributors to disease onset, progression, or misdiagnosis. In some cases, a sleep disorder may be the earliest manifestation of an underlying neurological illness. In others, disturbed sleep can worsen neurological outcomes or mimic primary neurological disease.Through a collection of real-world, case-based scenarios spanning patients across all stages of life, Sleep Medicine illustrates how commonly sleep disorders present in neurological clinics and hospitals. These cases emphasize practical decision-making and clinical reasoning, guiding readers through recognition, evaluation, and treatment.Clear, focused, and clinically relevant, this book equips neurologists with the insight and confidence to address sleep disorders effectively-improving outcomes and quality of life for patients whose neurological health depends on restorative sleep.