Learn Functional Programming The Fast Way!: A former Java/OOP instructor teaches FP in the fastest way he knows Paperback – March 31, 2023

This reads to me like an advertisement for his other thicker books, as he keeps referring to them on every other page.The other half of the book's content (that which is not referring to his older books) is, in my opinion, not much about functional programming at all. At one point in the book he is showing how to use the new types we have learned about (try, option, or either) and keeps stating that if you would like to see an implementation using the FP approach, to look in the appendix. Given the title of the book, I would expect the FP approach to be the main content of the book, and then refer to the appendix for how an OOP approach could be.If you do get the book, I would suggest you start looking at the appendix first, as that seems to be where he put the FP stuff.