An actuary is a professional with advanced mathematical skills who deals with the measurement and management of risk and uncertainty. The name of the corresponding field is actuarial science which covers rigorous mathematical calculations in areas of life expectancy and life insurance. These risks can affect both sides of the balance sheet and require asset management, liability management, and valuation skills. Actuaries provide assessments of financial security systems, with a focus on their complexity, their mathematics, and their mechanisms.

William Morgan, FRS was a British physician, physicist and statistician, who is considered the father of modern actuarial science. He is also credited with being the first to record the "invisible light" produced when a current is passed through a partly evacuated glass tube: "the first x-ray tube".