"An Introduction to Functional Programming Through Lambda Calculus" by Greg Michaelson - takes you on a journey from very basic lambda calculus, to how that evo

"An Introduction to Functional Programming Through Lambda Calculus" by Greg Michaelson - takes you on a journey from very basic lambda calculus, to how that evolves quite naturally into an ML-like language: https://www.macs.hw.ac.uk/~greg/books/gjm.lambook88.pdf https://www.macs.hw.ac.uk/~greg/books/gjm.lambook88.pdf We covered lambda calculus at university (at HW actually) and I'd played with SML/NJ and OCaml before. But seeing the lambda calculus abstractions being constructed over and over to create numbers (which I'd covered) and types and things, then finally become recognisable as ML was a real "ahaaa" moment for me.