Do you think that functional programming is something complex, accessible only by a programming guru? This book will debunk the myth of elitism and allow any programmer to easily understand the intricacies of the code. From familiar and simple OOP ideas, you will move on to FP, considering it with simple examples, exciting exercises and a large number of illustrations. You will begin by solving simple and small tasks that illustrate basic concepts such as pure functions and immutable data, learn to write code that is devoid of typical errors due to the presence of a complex distributed state, and understand the approaches to implementing I/O, parallel execution and streaming data. By the end of the book, you will be creating clear functional code that is easy to read, test and accompany.