After some 30 years of doing such work, I have concluded that classroom teaching … is perhaps the most complex, most challenging, and most demanding, subtle, nuanced and frightening activity that our species ever invented.
— Shulman, L. (2004). Professional development: Leaning from experience. In S. Wilson (Ed.), The wisdom of practice: Essays on teaching, learning, and learning to teach (pp. 503-522). San Francisco: Jossey-Bass.