Algorithms can be dramatically affected by the language in which they are implemented. An algorithm that is elegant and efficient in one language may be ugly and inefficient in another. If you have ever attempted to implement an assignment-intensive algorithm in a functional programming language, you are probably more familiar with this phenomenon than you ever wanted to be! But this sword does not cut in only one direction. Functional programming languages are wonderfully suited to expressing certain kinds of algorithms in a clean, modular way, and researchers over the last five to ten years have greatly expanded the range of algorithms for which this is true.