[Excerpt] Congress has seen a renewed interest in questions related to the market for private health insurance since the passage of the Patient Protection and Affordable Care Act (ACA; P.L. 111- 148, as amended). Recent health insurance marketplace changes include a different way to purchase health insurance (exchanges) and a new system of categorizing the generosity of plans’ health coverage based on the names of various metals (e.g., bronze and silver). Some consumers may face different choices of health insurance plans than in the past. Not all consumers are comfortable with the various concepts governing which health insurance plan might be best for them. This report provides an overview of private-sector (as opposed to government-provided) health insurance. It serves as an introduction to health insurance from the point of view of consumers under the age of 65 who purchase a health insurance plan. No background in health insurance is assumed, and all terms are defined. The report therefore can be viewed as an introduction to the more comprehensive discussion of health insurance found in the Congressional Research Service (CRS) health insurance primer.