The programming paradigm that emphasizes the use of functions as the primary building blocks is known as the functional programming paradigm. This approach focuses on the evaluation of functions and avoids changing state or mutable data, leading to more predictable and easier-to-test code. Key concepts include first-class functions, higher-order functions, and the use of pure functions to transform data. Functional programming languages like Haskell, Lisp, and Scala promote this paradigm, encouraging a different way of thinking about software design and problem-solving.