In this report, we describe the implementation of a minimal version of Lisp for use in teaching programmers who have some experience in another language. We discuss the reasons why learning Lisp is beneficial, and what such a minimal language might achieve. After mentioning other Lisp dialects which are minimal, we explain why these do not meet the needs we identify. We then report on the design and philosophy of our newly created language, Mary, and the most important features of this dialect. This language is placed in the context of other research and we report on the extent to which Mary meets our design goals.