SICP Lecture 1B: Procedures, Processes and Substitution

HN commenters hold it up as an unmatched introduction to programming and quote Sussman's line that knowing a spirit's name gives you power over it.

Lecture 1B of MIT's 6.001 Structure and Interpretation of Computer Programs (1986) with Gerald Sussman, covering procedures, processes and the substitution model. It includes the line about the power of naming things.