Regulation, like taxing and spending, is a basic function of government. Each year federal agencies issue between 3,000 and 4,000 final rules on topics ranging from the timing of bridge openings to the permissible levels of arsenic and other contaminants in drinking water. Unlike taxing and spending, however, the costs that non-federal entities pay to comply with federal regulations are not accounted for in the federal budget process. Some policy makers have expressed an interest in measuring total regulatory costs and benefits. However, measuring total regulatory costs and benefits is inherently difficult. This book provides an analysis of the estimate of total costs of federal regulation with a focus on the regulatory costs on small firms.