PyPy is a project that began in 2002 to create a Python interpreter written in Python. Over 10 years the project went through many stages of development including experimenting with different backends like LLVM and eventually achieving a breakthrough in 2005 where PyPy was able to run on its own after whole program type inference and translation to C. The document outlines key milestones and discussions in the development of PyPy over its first 10 years.