In 1984, John Hughes wrote a seminal paper titled, 'Why Functional Programming Matters,' in which he eloquently explained the value of pure and lazy functional programming. Due to the increasing importance of the Web and the advent of many-core machines, in the quarter of a century since the paper was written, the problems associated with imperative languages and their side effects have become increasingly evident.

This talk argues that fundamentalist functional programming-that is, radically eliminating all side effects from programming languages, including strict evaluation-is what it takes to conquer the concurrency and parallelism dragon.

Programmers must embrace pure, lazy functional programming 'all the way'-with all effects apparent in the type system of the host language using monads.

A radical paradigm shift is the answer, but does that mean that all current programmers will be lost along the way? Fortunately not! By design, LINQ is based on monadic principles, and the success of LINQ proves that the world does not fear the monads.