The most useful functional programming pearls to start with are currying, composition, and higher-order functions. Currying is a technique used to reduce a multi-parameter function to a series of single-parameter functions; this is often used for type inference, higher-order abstractions, and partial application. Composition is a concept which takes functions as input, combining them together to form a new function with the same functionality as its component parts. Higher-order functions are functions which can accept functions as arguments and/or return functions as a result. By mastering these fundamental concepts, you will be well on your way to understanding the foundations of functional programming.