Sleep significantly impacts health. Insomnia, characterized by difficulty with sleep onset, maintenance, and subsequent daytime symptoms, is increasingly prevalent and increases the risk of other medical comorbidities. The pathophysiology involves hyperarousal during non-REM sleep and altered sleep homeostasis. The 3P model explains the development and persistence of insomnia. Assessment is primarily clinical and based on appropriate history while distinguishing from other sleep disorders. "Somnomics" suggests a personalized approach to management. Cognitive behavioral therapy for insomnia is the first-line treatment in addition to other nonpharmacological strategies. Medications are a secondary option with weak supporting evidence.