Insomnia is a sleep disorder characterized by the persistent difficulty in falling asleep, staying asleep, or waking up too early and not being able to fall back asleep. It is a common problem that can significantly impact an individual's overall health, well-being, and daily functioning. Insomnia is relevant to the topics of 'What Is Consciousness?' and 'Sleep Problems and Disorders' as it is a sleep-related issue that can affect an individual's level of consciousness, cognitive function, and overall quality of life.