Scala is often touted as a tool for Functional Programming, but Functional Programming (FP) itself is left to differing and opinionated definitions by many of its practitioners. FP is a well defined approach to writing programs that we will uncover in this talk. It is a style that long predates Scala and many of the modern abstractions that are often referred to as "essential" tools. We will walk through the origins of FP, providing historical context through Lisp and the research that brought us this paradigm. We'll define what FP is and what it is not, looking at how tools like purity and immutability enable the expressions at the heart of FP. Finally we'll talk about practical approaches to Functional Programming in Scala, how you can and why you would use this style in your everyday work. This will _not_ be a talk about monads and type systems, but give you a pragmatic look at how to separate the syntactic sugar from the underlying principles.