The course introduces the functional style of programming. It covers basic properties of the functional programming like: the side effect-free programming, functions as first-class values, high-order functions, recursion, pattern matching, or function closures. Also, course introduces selected data structures like a list and a tree and a functional style of working with these structures. As a programming language, Haskell will be used. It is a pure functional, statically typed, lazy evaluated language.