This Note discusses key components of an insurance policy, layers of insurance coverage (including primary, excess, and umbrella), types of insurance coverages (including first-party coverage versus third-party coverage), deductibles and self-insured retentions, policy limits, and coverage triggers (claim-made versus occurrence-based coverage). It also discusses the types of insurance that are most relevant to commercial insureds, including commercial general liability (CGL) insurance, commercial property insurance, directors and officers (D&O) insurance, errors and omissions (E&O) insurance, employment practices liability insurance (EPLI), workers' compensation insurance, pollution or environmental liability insurance, and cyber insurance.