Knuth’s interest in storytelling also led him to develop a philosophy of literate programming — a method for writing computer programs as literary essays. A literate program intersperses source code with elegant prose written in a familiar language, such as English. The source code delivers functionality and efficiency, while the exposition addresses a human reader, rather than the computer’s compiler. Anyone who later updates or debugs a literate program will avoid the often time-consuming and costly problem of trying to understand the original programmer’s algorithms, design decisions and implementation strategies. Knuth is a computer scientist who understands that words matter.