Here, Erik Meijer and Philip Wadler discuss the theory and practice of programming language design with C# program manager Mads Torgersen.
Philip is widely known for his significant contributions to functional programming (including Haskell and a classic book - Introduction to Functional Programming(Prentice Hall publisher) that is one of the best introductions to functional programming you can find) and programming language theory. You've learned about Mondas on Channel 9. Well, Philip is the guy that is in part responsible for their wide adoption in FP.
Erik, as you know by now, is co-creator of LINQ, functional programming master, creator of the now unnamed "Volta" technologies, and much more.
This is a great conversation on how theory winds its way into practice and how principles take time to embed themselves into modern language design (most modern languages are built on the ideas formed many years ago, as theoretical principles). Phillip and Erik also touch on langauge history and futures. Tune in.