If you have a Disney Streaming account in 2022, you are a consumer of functional programming (FP) code written in Scala - what I call "Scala/FP." Similarly, if you have online financial accounts, read various online news sites, or use a gambling site like Caesars, you're also consuming content generated by Scala/FP code. Because of the concepts you'll see in this book, Scala/FP code is trusted, rock-solid, and is used in massively-parallel programming and streaming environments.As affordably as possible, to help OOP developers who use languages like Java, Kotlin, Python, and C++ learn the concepts that take you to the cusp of using Scala's two main FP libraries: Cats Effect and ZIO.The book that in less than 250 pages of text that are written in a simple, conversational style - just like I was pair-programming next to you - with plenty of code examples.