Worth noting that while functional programming is experiencing a resurgence right now, it’s by no means new.
It has it’s roots all the way back in the 1930s when Alonso Church first started writing about lambda calculus! Functional programming has been codified and promoted at least since John McCarthy’s creation of Lisp in the 1950s at MIT! Haskell and Erlang have both been around since the 1980's.
Great overview post. Thanks for writing it, and I enjoyed reading it. Just wanted to chip in a bit of historical context!