Dynamic vs. static typing is a debate that programmers, and programming language designers, have had for many years.  Is the flexibility of dynamic typing a decent trade-off from the safety of static typing?  Is one really more (or less) safe than the other? In this talk, Paul Snively and Amanda Laucher explore the different ways in which languages implement types, and how we can (and should) think about them, their tradeoffs, and how to use them effectively.